What cities to visit in about 10 days without a car?

I'm suggesting you don't buy a German flexipass at all. A Deutschlandticket for local and regional travel combined with single tickets for long distance trips is probably a better idea.

As for the itinerary, if that is what you want to see, it seems like a reasonable plan. But, have you considered focusing on northern Germany instead? It seems like many americans equate Germany with Bavaria but there is a lot to see in the north as well that is well worth a visit. And is a lot closer if your trip begins and ends in Berlin.

I didn't end up going as I went to England instead.

To Badger: "I am Canadian lol Nontheless, to answer your question, who knows if I will ever go back to Germany as my goal is to see as much of Europe. Maybe one day, I will return, but not before visiting most of the European countries out there. With that said, since I have a limited time in Germany, I want to make the most of it, so if I did the Northern cities as you say, that means missing out on Bavaria with the possibility of maybe never ever seeing it which I think would be a shame.

since I have a limited time in Germany, I want to make the most of it

Makes sense to me. The real question here is what constitutes "the most." That's hard to decide without prior experience... so your itinerary depends on your Rick-book in part and on the advice you are asking for here.

For me, "the most" entails not wasting travel time and $CAD on peripheral stuff that really won't improve your understanding of Germany or its people. IMHO you should definitely scuttle those two specific day trips from Munich. In both cases, you already know what you're going to see.

- I like that you have ample time for Berlin. 4 nights might be enough, however. Potsdam might be part of that.

- And I would keep the Rhine as well. It's totally different from Berlin for sure, but at the same time a place that's loaded with a variety of lessons, experiences and choices. IMHO Rick makes an unreasonable fuss over Bacharach. I would focus instead on Cologne (Cathedral, museums,) on Burg Eltz (a detour) and Marksburg (Braubach) castles, a hike on the Rhine Castle Trail and some time meandering some through some old-world wine towns like Oberwesel, Braubach, Boppard (great chairlift ride there) and Limburg (Lahn River,) and yes, 1-2 hours in Bacharach as well. And you probably shouldn't resist taking the Bingen > St. Goar Rhine cruise. I would allocate 3 nights for the area. TIP: Book your nights in Boppard to receive a free train + bus pass for unlimited local train trips throughout your stay.

https://www.boppard-tourismus.de/en/accommodation/

...missing out on Bavaria with the possibility of maybe never ever seeing
it which I think would be a shame.

- You will have time to see see some of Bavaria too...

Rothenburg: Worth seeing, and worth a day trip by train for a visit, but not worth 20% of the nights you have for Germany. NUREMBERG is the ideal Bavarian base town, IMHO, a fantastic city with a dizzying number of choices and great train connections with Berlin and the Rhine. I'd opt for 3 nights here. On one day you can day trip to Rothenburg in about 1.3 hours for a visit of several hours (preferrably on a weekday) very cheaply with VGN Tagesticket Day pass (€23, valid all day long for unlimited journeys within the VGN zone.) If you feel you must visit Munich, you can take a day trip from Nuremberg to Munich and back as well. But Nuremberg itself could easily entertain anyone for 2 days, I think.

The other outstanding Bavarian destination for your trip would be BAMBERG. And fortunately there are direct trains between Nuremberg and Berlin, so you can make a stopover in Bamberg for several hours as you travel between these cities. Bamberg station has lockers for your bags.

Unless you have a lot of interest in WWII, 2 complete days in Berlin would be enough. It is my understanding that my favorite sight in Berlin, the Pergamon altar, is not on display right now. I spent 1 1/2 days in Berlin in 1990, while on a tour, and I have never had any desire to return.

I have been to Berlin 5 times and still haven't seen everything that looks interesting. 5 days would be a minimum for me.

Another vote to stay in the north and visit Hamburg, Dresden, Lübeck, Quedlinburg, Celle, Leipzig, etc. There are gorgeous castles and palaces up north and beautiful scenery.

+1 for Ms. Jo. It's very personal, but I found Munich to be over-rated. You could put it off until you are doing, say, Vienna and Salzburg. I have not been to Neuschwanstein, but this board warns that it is not a very old castle, but more of a "medieval-revival style mansion". I'd add Leipzig, Weimar, and Erfurt to the list of other possibilities. Sadly, there are plenty of other KL sites besides Dachau. The regular city bus in Weimar has a route to Buchenwald. And Weimar has a rich literary and musical history, not to mention the Bauhaus.

It's possible to argue that you should have a break between Berlin and Dresden, because there are so many brilliant museums in each of them. Someone interested in contemporary art might go to Kassel. If you end up in Cologne, you could possibly fly home from Brussels. But we took a two-segment flight TO Cologne from the US that cost no more than the direct flight to Lufthansa "hub cities."

I have been too Germany many times most mid to south Germany with a trip to Hamburg. Never went to Berlin and never had a desire too. My two sons (in mid 20s) went to Berlin this summer and definitely did not like it. They were on a multi country trip and had been to Germany before. Everybody has their own tastes but I would recommend definitely doing a lot of research on Berlin to ensure it is the experience you want. It is not like Munich or other southern German cities. A great northern German City is Hamburg. If you really do not want to miss out on Bavaria, and in my humble opinion you should not, skip Berlin. Full disclosure I have Bavarian heritage. I would add a day in Munich and spend two nights in Berchtesgaden (see Hitler's Eagle Nest, boat ride on Konigsee (get off at end of the lake and hike to Obersee), Ramsau, hiking in the national park). Other great spots in Bavaria are: Nuremberg, Regensburg, Passau and Augsburg for a more urban experience. Other great sites include: Zugspitze, Hohenschwangau (right next to Neuschwanstein), Linderhof, Ettal Abbey, Weiskirche, Oberammergau, Garmisch-Partenkirchen, Mittenwald, Fussen (list up till now are all relatively close to each other), Herrenchiemsee and Burghausen (the castle there is incredible). You could also spend more time in mid Germany since you will be in Bacharach. I would recommend going to Eltz Castle and taking a boat trip along the Rhine. Another great site more to the south but not in Bavaria is Heidelberg both the town and the castle.

Wow so many ideas, I don't know which one to implement, I am even more confused now with my itinerary. Maybe this will help, I like anything with beautiful scenery (ex: neuschwanstein castle, Rhine River) and anything with history (like WW2 for example).

Near Berlin, there are 2 KZ, Sachsenhausen and Ravensbrück. Both have very well done exhibits, but Ravensbrück always touches me a bit more, because it was a KZ for women. There were women there from all over Europe, those who had been picked up as spies or being in the Resistance, lots of Jehovah Witnesses, Roma, Sinti, and Soviets.
If WW 2 is your main interest for this trip, then Berlin is the city for you. Head to Track 17, the Olympic stadium, Wannsee Villa and all of the memorials in Berlin itself.

With that said, since I have a limited time in Germany, I want to make
the most of it, so if I did the Northern cities as you say, that means
missing out on Bavaria with the possibility of maybe never ever seeing
it which I think would be a shame.

On the other hand, if you did Bavaria as you say, that means missing out on northern Germany with the possibility of maybe never ever seeing it which I think would be a shame.

If you want to go to Bavaria, by all means do it! There is a lot to see there. But there are some mixed opinions about Neuschwanstein here, some think it's just overrated and overrun by tourists. And there is certainly some truth to that, and there are many other amazing palaces in Germany to visit. And the Rhine valley is a very nice place to visit. But Rothenburg o.d.T. is one of the most overtouristy places in Germany, while it is worth seeing there are many other charming small towns in Germany. In the north there are also great cities to visit like Hamburg, Dresden, Lübeck, Leipzig and more.

Unless you have a lot of interest in WWII, 2 complete days in Berlin
would be enough

I strongly disagree! Even if you are not interested at all in WWII and the cold war, you can easily spend a week at least in Berlin. There is so much to see there. Add Potsdam to the mix and there is even more. And no offense, but you can't judge Berlin based on a 1.5 day visit in 1990.