TWRP is definitely on my phone. its where I land if I reboot into recovery (I assume it has become part of the Xiaomi EU ROM for Mi 11 since a A12 compatible version was created). Apparently it was implemented without the need for said folder(?)Omg - you should have checked that before posting two posts about TWRP
Anyway, various apps use various methods to detect unsecure environment (Bootloader unlocked, not-stock ROM, etc).
I don't use your eGov app and have no idea.
Ask if somebody else uses, and precisely which app
Btw, there are a lot of discussions about hiding from this and that app and how in General Magisk thread - but it requires Magisk/root and its modules. You could check also there
the app in question is "Digitales Amt"
it starts fine but once you try to login it will show an integrity check message and close itself on my phone.