Help with trains please!

The top resource for train travel, once a blog and now an institution, is www.seat61.com
Among other things, the Man in Seat 61 has lots to say about passes. You can only be sure about the costs by first working out the point-to-point prices, with his links as help. Keep in mind that some long-distance trains require reservations, which are included in point-to-point while passholders have to purchase them separately, at a cost in money and nuisance. For the longest rides you can also compare Europe's web of no-frills airlines, being aware of extra charges not stated on the companies' opening pages and the extra time to get to and from airports. www.skyscanner.com

A very complicated question, you sound like you are floundering.
Start with this website. it is the best explanation on the web: https://www.seat61.com/
And as far as passes are concerned, read this page: https://www.seat61.com/Railpass-and-Eurail-pass-guide.htm

As far as what you are listing you have 5 countries involved: Italy, Switzerland, France, Belgium and the Netherlands.
"the train schedules and info are super confusing to me" - probably because there are so many trains. Just assume you can get from anywhere to anywhere by train, many times per day and in many cases every hour. You can fix exactly which trains later.
You also need a good map that shows rail lines, NOT a road map.

Some generalisations. A rail pass is never good value in Italy, normal tickets are cheap.
A rail pass, or a ½ price pass, is often good value in Switzerland.
For France, Belgium and the Netherlands, a pass is usually not good value. There are extra costs for some when using a pass trains, and you are not making many trips.

I count the following trips:
1) Rome to Florence.
2) Florence to Venice.
3) Venice to Milan (not Turin), to Tirano, Bernina pass route to Chur.
4) Chur via Glacier Express to Visp (not Zermatt, you would have to double back to Visp, look at a map), to Interlaken, (to xxx?)
5) xxx to Interlaken to Paris.
6) Paris to Amsterdam.
Is this all?

1+2+3 as far as Tirano, Italian advance purchase tickets, cheap.
3 from Tirano + 4 + 5 as far as Swiss border (Basel), PROBABLY a Swiss half price card plus ½ price tickets.
5 from Basel to Paris + 6, advance purchase tickets.

Does this make sense?

P.S. 6 trips in 5 weeks, that is staying in 7 places, 5 nights each average. Or had you planned to stay in some other paces en route?
You need to make a list of place, with how many nights in each. That gives you your list of train trips.

After taken in the trustworthy information from Man in Seat 61, the first thing to do is to open the pan-European train planner of the Deutsche Bahn, the German railway company. It is a marvellous tool to find out which trains are available.
For the real cost of point-to-point tickets, you must go to the relevant national railway companies. For Italy that is Trenitalia and for France, including the trip to Amsterdam, the SNCF. (I am not acqainted with the Swiss railways.) Put in the dates you want to travel, and you'll see the price of advance bought tickets. These come mostly with huge discounts, but are non-refundable and only valid for that specific train.

Just to be sure...As Chris just pointed out you want to go Tirano not Turin.

Multi-country train passes do not include city transport. You will need to look at each city to find their multi-day passes. The Swiss Travel Pass does include urban transport, but only in Switzerland.

You have plenty of time for this and the first part, Rome to Venice is straight forward, as is the second part of Switzerland to Paris then Amsterdam. You can buy discount nonrefundable tickets now, once you have finalized your itinerary.

The middle part in Switzerland is where you need to nail things down. You will be there in mid to late October, and the high resorts like Zermatt, Wengen and Muerren can get snow that time of year, so be prepared. Also, the sun will be setting between 6 and 7 and mountain valleys will get dark before that, so take that into consideration when booking scenic rail trips. Daylight Savings Time ends Oct 28 in Europe, but you should be out of Switzerland by then.

The Bernina Express and Glacier Express require seat reservations, the the cost of those is not reduced by a Swiss travel Pass or Half Fare Card. Because the straight through Bernina Express to Chur gets in after 6 pm, the light be be fading. Take the early one as far as St Moritz and spend a night there, then take the Glacier Express in the morning from St Moritz. The first part to Chur covers the exact same track as the Bernina Express.

Do you want to spend time in Zermatt? Since it is a year-round ski resort, it will be open as usual. If you don't want to spend time there, do as Chris suggests and get off the Glacier Express at Brig and take a train to Montreux from there.

You could also go to Interlaken from Brig, then the Golden Pass to Montreux and go to Paris from nearby Lausanne on a high speed train.

Finally, for the route from Venice to Tirano, I might suggest a stop in Varenna Italy on Lake Como for a few days. You have time and it is on the train route from Milan to Tirano. That way, you could get to Tirano in the morning to take the early (10 am) Bernina Express to St Moritz.

Trains in Switzerland are all the same price, and unreserved except the Glacier and Bernina Express trains which have panorama cars and upgraded meal service.

So now is the time to decide where and how much time to spend in all these cities. Should be a good trip.

I count a total of 8 travel days ...:
1) Rome to Florence
2) Florence to Venice
3) Venice to Lugano/Tirano
4) Bernina Express to Chur
5) Glacier Express to Zermatt
6) Zermatt to Interlaken
7) Interlaken to Paris (via Basel)
8) Paris to Amsterdam