Three different itineraries

Is there a particular reason you are zigzagging rather than a smooth circle?

No real reason - it just seems hard to include both the Golden Pass and the Glacier Express without doing that. Do u have a suggestion for a route that would include both? Or should I just concentrate on the Glacier X and the Bernani Express since they connect? Thx, Jim

Eight nights is a little difficult for what you're planning . Any way to squeeze another night or two?
How do you feel about going to Zermatt and have the summit fogged in the entire time? I'd delete Zermatt and add the days to other stops. Also, perhaps delete Lausanne and save this area for another trip.
Lucerne needs another night, at least. There are so many summits you can access from Lucerne. And-What if your plane is canceled or delayed? Are you coming in from overseas?
Gimmelwald is too tiny, I'd stay in Murren (or Wengen) and add as many nights as possible.

And I think it's too many train rides. After awhile, I don't think it will be interesting. And bad weather would hinder your enjoyment with so many train rides. I would prioritize the Bernina Express route, even if you rode it down to Tirano and back. We did something similar - it was incredible seeing the views from two different directions. And you can ride the regional trains, with more schedule options, which use the exact same tracks.
Another option , with more days, is coming into Milan>,Varenna, Lake Como> Tirano > Bernina Express route> Pontessina> Berner Oberland> Lucerne.

Just some ideas- what are your priorities in this beautiful country, at a great time of year. Safe travels!

The Glacier Express runs along the south side of the Alps, connecting Zermatt with St. Moritz via Chur. It goes nowhere near Gimmelwald,, on the north side of the Alps. The only option among the ones you list that includes the Glacier Express is #2, but this one does not have the Bernina Express (St. Moritz to Tirano). Actually none of your options includes the best part of the Bernina Express, from St.Moritz/Pontresina to Tirano.

You can see the scenic trains highlighted on the map of the Swiss rail system:

https://www.travelswitzerland.com/en/download/swiss-travel-system-map-en-2023/?wpdmdl=14294&masterkey=63a023c8da36c

If you want to include all 3 scenic trains without a lot of detours I suggest the following route, flying into and out from Geneva instead of Zurich:

The route is Geneva airport to somewhere along Lac Leman, maybe a smaller town such as Morges or Vevey, for your arrival night. Then here to Zermatt for 2 nights. Glacier Express whole route to St. Moritz ( or Pontresina, where most people prefer to stay) via Chur. Stay 1 night in Pontresina (or Samedan or Celerins, wherever you find lodging that pleases you and your budget.

Next day take tha Bernina Express or a regional train in the same tracks to Tirano on the Italian border. That is about 2 hours. From here you have 2 options: either continue on the Bernina Express bus to Lugano for your overnight stop, or change to an Italian train and ride another 2.5 to 3 hours to Varenna or other town on the east side of Lake Como for your overnight.

If you choose Lugano, you can take a train directly to Luzern for your next stop. If you choose this option, the whole journey is covered on a Swiss Pass. And you are not vulnerable to the strikes that can affect Italian trains. If you choose Varenna, after an overnight there, you travel I1 hour to Milano Centrale, where you board a direct train to Luzern. The part of this route that is in Italy Tirano to Varenna to Milano Centrale to Chiasso) is not covered on the Swiss pass but is not terribly expensive.

Either way you end in Luzern for 2 nights. Then you ride the Golden a pass train to Montreux, and either spend the night there or, if this is the night before your flight, you move to a town closer to Geneva and the airport.

I believe that is 8 nights and 6 hotels, like your option 3. But it has you riding the actual Glacier Express route, and the Bernina Express from Pontresina to Tirano ( the best part), which your Option 3 does not.