I've installed Krita 126.96.36.199-2 build date 12/09/2019 from the extra repository in Manjaro 20.02 for the raspberry pi 4 b and I get a symbol lookup error that prevents startup.
krita: symbol lookup error: /usr/lib/libkritaui.so.18: undefined symbol: _ZN20QOpenGLFunctions_2_114versionProfileEv, version Qt_5
FWIW, I attempted to build Krita myself, but I ran into some issues with the gpg checks. I'd prefer to get the repo build working anyways. If there is any helpful information I can provide, let me know!