Fun fact - GDPR is about European persons, not European servers. If an European citizen has a fediverse account on an American/African/Asian/… server and Meta collects all of their data and processes it, they are still in violation of GDPR. Locking European (Instagram) accounts out of Threads doesn’t make them comply magically with GDPR.
Good luck meta, have fun handling all those GDPR requests and proving that Europeans have consented that you suck up all their data…