LinkedIn locked my account and wants me to do ID verification through Persona
(piefed.cdn.blahaj.zone)
Snail mail with tracking, I gave them my legal address (moved shortly after) and email as verification. I requested the deletion of all my data but never actually regained access to my account. There are plenty of templates online so you use the correct wording, set an appropriate deadline, etc.
Eventually my account disappeared, but I never received any actual confirmation from them.