Launcher crashes after today's update(SteamPlay Linux)

Issues for my as well on Gentoo with the custom launcher which I’ve used for years. The launchdarkly copy thingy didn’t work. However, I solved it this way:
Launcher → Settings → Wine options
Unchecking “Use dev versions” and choosing the oldest version that was available (wine-1.9.9-ccp-daily-10). “Use custom Wine” was already unchecked since earlier.
After exiting and killing all evelauncher and wineserver instances and restarting the launcher, the game launched properly again.

Hey, same issue here.
Playing for more than 1 year with
Steam - proton 5.0-10 - Kubuntu
Launcher start but client crash since last patch 19.09 october 13