??? in usernames

Hello!

I have been googling the issue a bit, and I was wondering if anyone has a solution on how to get ??? and ??? as accepter characters as usernames in wordpress. I tried this plugin: https://sv.www.ads-software.com/plugins/wordpress-special-characters-in-usernames/

Sadly it did not help, even when I tried to write a regex in the plugin code like this:
^[a-zA-Z0-9??????]+$

Does anyone else have a solution for this?

Thank you!

Best wishes,
Kasper

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