I'd like to request a new Alt Main subcategory in the appropriate thread, but it seems to be locked, possibly due to inactivity or age. Should I make the request here, or is it possible to unlock the requests thread?

Sorry about that. You can post in there now, I think it was locked by mistake. If you haven't joined the discord already, you can find a link to it here: https://discord.com/invite/NjQFEkc