Cant Unlink Old Minecraft Or Deactivate So Now What?

So made this forums account a few years back when I was still using a family shared Minecraft account. Obviously I've now grown up a bit and gotten my own copy, leaving the old one to my sibling.
Now I'm in the dilemma of forums still being linked to the old account, unable to relink and cant deactivate?
The email, birthdate and other info on here are mine so I cant pass this account to my sibling easily. I don't have any other emails so creating a new email just for this would be very unhelpful and owning two forum accounts is against the rules here. So now I'm stuck in this loophole and any answers I find are just 'no'. I see a lot of other people with the same issues with no answers to be found.

I'm well aware I cant unlink or deactivate and after emailing support with no response I'm just looking for any helpful suggestions.

 

There's no option on the forums to change the linked minecraft character or date of birth, although you could change the email adress under Your Account->Contact details.

The support email is meant for store purchases rather than forum issues, for those it would be best to contact a mod or admin through discord or by sending a personal forum message.