Hey everyone, thanks four replies! That helsp alot.
So it sounds like the most usefull thing would be to dive into QML and make myself familiar with ubuntu clickable.
From that point on I could still decide wheter I want to go with C++, Rust or Python.
Thanks for all the links/recommendations that helps a lot. I will do some reading the next couple of days
I think whats missing (or maybee just didn't find)
swipe like keyboard a native whatsapp client dictionary apps (for offline use) e-book reader with dictionary support. ("sturm" is very good, but lacks that functionality) native music/video streaming clients (amazon?) banking apps (e.g. for two factor authentication) local public transport apps(I know some of that stuff is unlikely to be ever covered, but some gaps can be filled)