1. Right after install, go to steamapps/common/Thronebreaker The Witcher Tales/Thronebreaker_Data/StreamingAssets and rename or remove the videos folder. They don't work, and they break the game.
2. Wineprefix must be reset after every launch. I'm not sure why it breaks in the first place, that's my first experience with that kind of thing. Good news is, it can be done with one command, and you don't even have to use the same Wine version.

• Automatically: go to Properties > Set Launch Options and type wineboot; PROTON_NO_ESYNC=1 %command% . You're good to go, now it will automatically reset on every launch.
• Manually: open steamapps/compatdata/973760/pfx/drive_c in terminal and type something like WINEPREFIX=$(pwd) wineboot.
• Launch the game 3-4 times in a row to make sure you got that right.

3. After first launch, go to game settings and turn off VSync, this will remove unpleasant stutter.

Stability issues are fixed with PROTON_NO_ESYNC flag.

If mouse is broken and you can't click anything, press and release Alt, then Ctrl, then Shift, then Super and it should work then (modifiers just get stuck sometimes).