If I don’t alt-tab the game doesn’t break.

It’s likely the 560 driver on Wayland being the culprit here. Specifically resizing XWayland windows. You could try running nvidia-smi in a terminal and see what specifically is causing this VRAM spike.

Reports of excessive VRAM usage with the 560 driver on Wayland. See this for a potential fix. Hope it helps

https://www.gamingonlinux.com/ is a wealth of information, of which, I am not willing to let go, as it is a resource of current news that is very relevant to this “Linux Gaming” sub. So no; I will not stop linking https://www.gamingonlinux.com/ to this sub just because you got butt hurt.

RIP our wallets 😓

If you’re only going to pick Pop!_OS or Manjaro, I’d suggest you go with Pop!_OS. The Manjaro team has been very weird, and made some poor decisions in recent years. I’ve had a very good experience messing around with Pop on an Nvidia GPU.