Adding this here since I can't find this in searches.
If all your games fail to launch (nothing ever show up) even with ProtonDB Platinum games, then check that Proton must be installed in a Linux partition. If not, then move Proton to a Linux partition and validate its file (it is visible in Steam library as type "tool", similar to dedicated servers). After that close Steam, wipe your compatdata folder and it should work.
Is it really necessary to move compatdata to an ext partition and symlink it? It works just fine for me (I do have Proton and Glorious Eggroll installed on the ext partition however).
Is it really necessary to move compatdata to an ext partition and symlink it? It works just fine for me (I do have Proton and Glorious Eggroll installed on the ext partition however).
Without the symlink on the library that's on an NTFS filesystem, sometimes it seems to be fine, with the compatdata automatically going to the default library's compatdata, but sometimes it doesn't automatically go there and the game then won't work correctly or may not launch at all. Adding the symlink to a location on a filesystem compatible with Proton removes this inconsistency. But again, don't do as the instructions say exactly. Give each library its own compatdata, do not share.
Nothing extracted yet.
In reference to the linked section of this wiki page: https://github.com/ValveSoftware/Proton/wiki/Using-a-NTFS-disk-with-Linux-and-Windows#preventing-ntfs-read-errors
Each Steam library on NTFS should have its own entirely new folder made for its compatdata on the Linux partition with the symbolic link being created to point to it, and absolutely should not use the default Steam library's compatdata or an existing compatdata folder from any other Steam library.
When attempting to use Steam to move a game between two libraries sharing the same compatdata folder, all of the game's files in compatdata will get deleted in the process because it doesn't know they are the same. Technically that could be fixed so it detects that and just leaves the files alone, but until then, the folders need to be separate.