I have also opened an issue on Frontier's issue tracker: https://issues.frontierstore.net/issue-detail/68387
Ive been running into the same issue as well on Nvidia 1660 super
If you're on 550, try to upgrade to a newer driver if you can and see if that helps. I'm unable to install 550.127.05 to check that specifically (the installer fails), and according to the author an upgrade resolved the issue (https://github.com/ValveSoftware/Proton/issues/8221#issuecomment-2466771355).
im currently on nvidid driver 550.120-0ubuntu0.22.04.1 and dose not work
proton experimentalx1 2024-11
There are severe rendering problems in Planet Coaster 2. According to protondb, this seems to be only affecting NVidia GPUs:
The globe doesn't render in the main menu:

While zoomed out, the game displays a brown "fog" over everything. This is an empty Sandbox save:

Zoomed in closely, some stuff renders, but not properly:

The issue disappears when the camera is close to water:

Software information
Planet Coaster 2, run directly through Steam with Proton Experimental. Different Proton Versions didn't seem to affect the issue, neither did changing the ingame graphic settings have any effect.
System information
Log files
Log Proton Planet Coaster.zip