@heX16 That would certainly be possible, if there is no other solution (like fixing the problem where it comes from).
I’d really appriciate if you could contact the MyPhoneExplorers and tell me what they say? Android account names can easily contain Unicode characters, for instance if you use local language. What if you name an account “Mein schöner Account”? Or “мой аккаунт”? Such names should work with any app, and they’re not related to DAVx⁵.