IIRC this was already addressed and should be automatic.
There was an issue specifically mentioning GDPR and the devs implemented a way to automatically delete the data of an account within the given time.
It’s not a GDPR request in itself, but AFAIK a normal delete account request should be compliant… INAL
That’s a weird read having in mind I had to move to Wayland because x11 had severe screen tearing. I would have guessed Wayland had better support.