It's not that easy. The site won't be GDPR compliant by just deleting your posts and changing your name. The way the site handles deleting posts is not GDPR compliant because quoted replies still contain your post and an identifier.
Worse than that, they contain the original username.
Personally, I'd hate if they fixed this.
> era deletes user, name is now Deleted User #644832
> quoted replies still say "riotous" which GDPR demands scrubbed
> era mods: areyoukiddingme.bmp
> knowing no other solution, staff ctrl+f replace every instance of text "riotous" with "Deleted User #644832" in the raw database
> problemsolved.mov
> use this method for dozens of requests without incident
> later, the user "woman" requests deletion