After all NVRAM and PRAM resets I held down command+option+shift+R This is supposed to be a combination to install macOS version it was shipped with, for me it was Catalina. Such a close call for my MBP2019. I shouldn't try to do clean reinstall of Big Sur from beta to release on Friday 13th 2020 - the worst combination.

Same here, iOS apps work. Even native macOS apps are fine. Only catalyst stuff is affected. I also opened an issue through Feedback Assistant app. Thanks for the suggestion with manual launch! 👌