How long does it take until usernames are recycled?
There's a username I've been waiting for 6+ months to get and it hasn't become available still, what do I do?
Usernames may be freed up for re-registration, without notice, if: are no longer active, meaning, there is no viewing or login activity associated with the account for at least 12 months.
Read more about the "Username Rename and Recycling Policies" here: https://help.twitch.tv/s/article/username-rename-and-recycling-policies?language=en_US
I hope I was able to help you. I myself had to wait 12 months until my username was released.