Missing Caldav support is really painful. I've had to spin up my own Caldav container (Radicale) and leave Proton Calendar behind, but I'm still unable to send calendar event notifications from any calendar app on mobile, only from thunderbird.
Gamescope is great but the fact that you can set multiple limits and switch between them makes me prefer MangoHUD, even though I also sometimes use gamescope (with Nvidia my experience with it has been a little bit hit or miss).
The latest driver makes Wayland usable on NVidia, as long as you use an up to date shell and the latest xwayland version, I've been using it since it came out and it's been great, games are much more smooth and the constant microstutter I'd been having with X is gone.
Check out if these updates are all available on Pop, if they are give them a try!
I've applied it system wide by setting `MANGOHUD=1` inside `/etc/environment`, which might be a little bit excessive but it works for me. You can also set hotkeys to toggle the Hud and the frame rate limits within ~/.config/MangoHud/MangoHud.conf, but I think there is a GUI tool that does it for you.
As for the frame pacing, try with the beta NVidia drivers (v555) and Wayland, though I don't use Sunshine so I'm not sure if it'll help.