Worse desktop graphics after Steam Play crash

I recently experienced reduced graphical smoothness in my system (Manjaro KDE) after a crash caused by a game run using Steam Play.

While it is not a terribly interesting story, I note it here in case someone (possibly me) encounter this again and might be helped by the solution.

The crash happened when I tried to run Baldur's Gate 3 Early Access (patch 8) with Vulkan (I should have picked Directx; patch 9 had reset it to Vulkan).

After rebooting the machine, I noticed the following:

• Transitions were less smooth, especially scaling up/down
• Transparency was no longer supported
• The alt-tab menu no longer displayed previews of the windows (just big ugly icons)

After fiddling with it for a while, this StackOverflow answer led me to the answer. Going to the "Compositor" section in the system settings (System Settings -> Display and Monitor -> Compositor), there was a message stating that it had been disabled due to a crash. Also shown was a button to re-enable the compositor, with a warning that if the issue behind the crash hadn't been fixed, re-enabling it might instantly crash things again.

Re-enabling it (and perhaps restarting?) returned things to normal.