7-10 days: Lake Como to St Moritz via Bernina Train or Como to Lugano or Venice?

Item 1 is better IMO.
Item 3, most people recommend Pontresina rather than St Moritz. It is just before you get to St Moritz on the Bernina Express.

thanks @sam when going from Como to Zurich- the its seems Lugano route more direct and 1/2 the time (30 minutes to Lugano) then 3.5 hours to Zurich vs 2 hours to Tirano > 2.5 hours to St Moritz >4-5 hours to Zurich.

With 3 days in Como region and 3 in Swiss in mind is the Bernina pass and ride twice as beautiful as the Lugano way to justify 2-3X the time on a train? I'm sure its gorgeous and voted one of the most scenic routes for a reason just wondering if the Lugano route is equally as gorgeous and would allow more time to be settled and explore little towns and villages

When is this trip going to take place?

If you are talking about "Looking for scenic Sound of Music meets Lord of Rings scenery", then Pontresina comes close. It is 4 hours from Varenna (across from Bellagio) to Pontresina with the Bernina Express, going over the Alps. Then it is 3 1/2 hours from there to Zurich.

If you are talking about Lugano, its a city. A scenic city, but still a city. After Bellagio, it might be a bit of a let-down. Right now it is 3 hours from Lugano to Zurich, and until the Gotthard Base Tunnel gets repaired, the trains use a scenic route that still has a sizeable tunnel under the high peaks. When the Gotthard Base Tunnel is back up, you will cut 1 hour off the travel time to Zurich, but go completely under the Alps.

Take your pick.

What time of year?
If coming from the US, I'd maximize your days because of the time lost to travel and jet lag.
Are you interested in actually staying in the Alps, such as in Wengen or Murren?
I rode the Bernini Express regional trains route - actually twice, since because at that time of COVID, we couldn't cross into Italy without quarantine. It was fantastic both ways ! Do a little research, so you'll appreciate the incredible 1900's engineering and building skills that were required, all with hand- done mathematical calculations.
We stayed in Pontressina, and it's beautiful, but if you're heading to Lake Como and/ or Venice, just do one day in Pontressina.
Flying into Venice is easier than flying out of Venice, especially if you have early morning flights. Just this May we flew into Venice, then into Lake Como, two of my favorite areas, to which I will return again.Lake Como is beautiful and relaxing, we stayed in Varenna.
You don't need 3-4 days in Zurich, if I understood that correctly. In fact, you can stay in Lucerne, much more charming than Zurich, the night before a flight ( 1 + hour train.)
Perhaps -
Venice > Lake Como > Tirano - Bernina Express route to Pontressina > Wengen or Murren > Lucern (fly out of Zurich). Have a wonderful time in one of my favorite countries. Safe travels!

@Pat & @sam wow! really appreciate the detailed through response- obviously i am gooling, youtubing and and reading the rick steves guidebook but some pointers from folks who have done the route is very helpful.

We are going Oct 28-Nov5. I guess I am debating the merits of como to zurich airport via eastern bernini route or more central thru lugon to lucerne that is 1/3-1/2 train time

seems Bernin express is one of best views in the world but with limited time its like 4.5 hours from belaggio (15 ferry 2 hours to tirano then 2.5 to st moritz or the apparently more scenic town right before. 3 days in lake como bellagio is 10/29-31 then 1 day to get to st moritz area. Flying out of zurich the 4th (so gf has day of rest before work on 6th) so basically my question is the 2-3 days are better spent in a town like lucern with the 2 hour train from lugano vs 8-10 hours going the bernin? moritz> chur> zurich route.

Like can we also see super beatiful vista on the lugano train and have more time to explore and stay in a quaint little mountain village/small town or is the bernin really once in a lifetime must see depsite the extra time?

any ideas or advice greatly appreciate

Question-
Are you coming from the US or are you already in Europe?
No one on this Forum, myself included, ever feels they have had enough time in Wengen/ Murren. I spent four days in Sept 2021, and it wasn't enough, and it was my second time in the BO. I will return.
Lugano was like La Jolla, ( I live in San Diego ). Rolex watch stores and other high- end stores, which are everywhere in tourist cities.
What are your interests , and how many days do you have?
You are in late shoulder season, so you do need to research what is open, such as lifts and hotels in the Alps. Some areas do take a break between fall and ski season.
Have a great trip!

@pat flying from New York in the US. Like quaint little villages to wander around, lux spa is cool but could care less about designer goods. Not really into hiking- just like cool little towns to wander and get lost, cafes, scenic views etc. Anywhere by water over cities. I lived in Italy for a year in college in Florence so did all the major cities etc
My dad just threw a wrench in my plans and said to avoid time wasted on travel maybe just post up the whole time in amalfi coast or lake como and take local day trips. Amalfi coast is one of my favorite places on earth but I have already been there. Is it silly to go back to the same place? My fiancé has never been to amalfi. Maybe just to go to amalfi and chill out. Then she suggested Greek islands bc neither of have been there and it looks cool but is it to far i to fall for them to be open?
Sorry I'm all over the place. Thanks for indulging me and sharing some advice I really appreciate it. At the end of the day anywhere in Europe is great just want to make a good plan

We were in Amalfi Coast this past May, and experienced horrible weather - rain, rain, rain. There are few indoor alternatives. Your dates are late shoulder season, and things start to close for a break before the holidays, Also, the weather can be unpredictable.
Venice is a great all- weather city, as it offers indoor and outdoor experiences.
Good luck with planning.

thanks @pat. i love the fall and dont mind its more quiet. thinking lake como > st moritz > zurich area to fly out of sounds marvelous. We have 2-3 days between St moritz and flying out of zurich. only takin train line from Chur to zurich area- are there quaint little towns or villages you recommend we stay for a few days? lets say 1 night St moritz 2 hours train to Chur- stay there or somewhere more scenic? seems like ~ 1.5 hours to zurich- is there a quaint village aree similar to berner oberland traditional village style more so than city or lux resort town to stay for a few days? getting closer to a plan thanks for the insight

We were strongly advised not to stay in St-Moritz rather to stay in charming Pontresina which we enjoyed. We went to see St-Moritz one day and we’re so glad we weren’t staying there. St-Moritz had modern buildings among the older ones and was not attractive.