15 character gamertag in 2022

Update: If I try a gamertag with 14 or less characters, it seems to move forward. However the character limit is supposed to be 15 and the new gamertag I want has 15 characters. :-(

Unfortunately there isn't much we can do about this. At least we have more characters than some of the other systems

Today more one user can have the same gamertag, for that the #0000 in front of gamertag like the Nick name of Discord For exemple. Because this, the gamertag is limited today for 15 character I tink

Partially true. Gamertags can have up to 12 (or 13) characters, if they choose one that's already taken, then they will be assigned a suffix.

"We’ve updated new Xbox gamertags to support a 12-character max, Unicode-based name of your choice, with an auto-generated suffix if the gamertag is shared. We now offer 13 different alphabets for gamers, which support more than 200 languages worldwide.

New Xbox players or those who want to change their gamertag can claim one of their choice, up to 12 characters. If a gamertag is already taken, a suffix with numbers is attached to differentiate you from other people with the same gamertag. Suffixes
are subtle so that the focus is on the name you chose, but they are always shown. "

https://beta.support.xbox.com/help/account-profile/profile/gamertag-update-faq

Today more one user can have the same gamertag, for that the #0000 in front of gamertag like the Nick name of Discord For exemple. Because this, the gamertag is limited today for 15 character I tink

If you have access to an Xbox 360, you can change your GT there and still use the "old" system which allows for 15 characters. This is the only workaround I know of that will get you past the 12 character limit, but unfortunately you would have to pay
the $10 name change fee if you have already taken advantage of the free name change.