I lived in Geneva for 18 years and my son and grandchildren still live there so I go quite often.
Now, you're only going for 8 days so that limits you a bit. Do try to get into the Valais (Martigny, Sion, Sierre, Zermatt, Brig). The views are spectacular and it's quite easy to get up the mountain on train or Funicular.
The lenses you take will depend on the kind of photography you want to do. Switzerland didn't really suffer during WW2 so there are lots of really nice urban shots in towns, cities and villages. Places like Fribourg and Gruyere or the old towns in Geneva and Lausanne. Bern is also really great for urban photography. For those, I mostly used my 17-55mm lens on my Nikon D500.
Obviously, there are lots of opportunities for mountain shots and you'll want both wide angle and a longer lens depending on what you want to shoot.
You can also get up onto the glaciers in a couple of the ski resorts (Crans-Montana, Saas Fe). Do a bit of summer skiing and get some interesting shots.
Also, don't forget that western Switzerland has lots of lakes (Leman, Neuchatel, etc.) so opportunities for different kind of shots and, probably, a longer lens needed for them.