OH MY GOD! It worked! I set up a third account with no random letters but a strong memorized passphrase.
I also have a clue why the second account with a shorter one (like 50) didn't work. Randomly hammering I hit letters like Ö Ü Ä which probably caused the issue.
A part of the old passphrase looked like this: (§UZJ&?$UKWP$%Ä*DT':W$T$ZAD;MÖAFMKÖBGM-;SDÖKN"(="Z%)