I'd love to create an English-oriented instance like en.misskey.io, but I'm kinda strapped for cash right now. Would you mind lending me a hand on pixivFANBOX? https://misskeyhq.fanbox.cc/
The reason we don't accept usage under the GDPR is because we've had users who demanded that we delete everything, including backups and data from other instances. That's just unreasonable, and apparently, GDPR doesn't allow for the costs of handling such requests to be charged. If you don't make any deletion requests or assert any rights under the GDPR, there's no problem with using our service from the EU or the UK.
(Although, officially, it's prohibited.)