July Itinerary Opinions Wanted

I would be concerned about whether lodging is available in Gimmelwald. There are very few places to stay there. You might have more options in Murren and Wengen.

Next, you are proposing staying in 7 places over 12 nights, if I’m counting right. I think that’s too much, by at least 3 stops. You need to sleep in Geneva the last night. So that gives you 11 nights elsewhere. Narrow down those locations to 2-3. Remember that the views you are going for are weather dependent. What if it rains for two days straight while you’re in Lauterbrunnen?

I'd eliminate Appenzell, too far out of the way. You can add to Zermatt and Chamonix.
1. go straight from GVA to Bern, 1 night there.
2. go to Luzern for 2 nights.
3. go to Gimmelwald for 3 nights, no use splitting with Lauterbrunnen, they are right next to each other (vertically).
4. go to Zermatt for 2 nights, better chance to see the Matterhorn.
5. go to Chamonix for 3 nights.
6. go to Geneva for 1 night
.

Way too many hotel changes - you're going to spend 70% of that trip traveling and checking in and out of lodging. Pick 3 spots to sleep and just do day trips via train if you have a non-negotiable place you must visit that doesn't fit within those 3 places. The Swiss train system is extremely efficient and instead of spending 1/2 of a day changing hotels just spend it enjoying a fun train adventure day trip. You aren't going to get to see all of Switzerland in 11 days and if you try to, you're not really going to get to slow down at all to actually savor any of it.

I’d also say skip Appenzell. The area is nice for hiking/walking but it’s a big detour when you have limited time and are not visiting anything else on that side of Switzerland. The Aescher guesthouse has become hyped up on social media, but you’d be better off adding more days to your other destinations. Your current itinerary involves way too much sitting on trains and not enough time on the ground (in my opinion). Agree with above poster: don’t get stuck on staying in Gimmelwald - Lauterbrunnen, Wengen or Mürren are all good options and more convenient.
Also not sure it’s realistic to explore Lausanne on the same day you arrive and then continue to Lauterbrunnen.
In fact, it might make more sense to go from Geneva straight to Luzern first (direct train from the airport once an hour, takes just over 3 hours) and then work your way back rather than zigzagging all over. After Luzern, head to Lauterbrunnen via Brünig pass (Bern day trip from Lauterbrunnen Valley rather than overnight is doable and good rainy day option), then to Zermatt if it’s a must see, and finally to Chamonix and maybe end in Geneva/Lausanne (44 min train ride from Lausanne to Geneva airport, direct train).

Personally, I would skip Berne & Appenzell. Add a day or two in Lauterbrunnen. Add a day in Zermatt. Skip Lausanne only because you will have to deal with luggage storage and jet lag. Use the train time to Lucerne to relax and regain some sense of time and place.