What do you have in mind? I am not aware of any foss platform, European or not, that is as accessible as Meta'a networks are. If you get asked about a server choice during the registration process, it's game over.
The sad thing is, we had social networks in Europe, things like Nasza Klasa and Hyves. But Facebook is ate them all, I'm not sure why. I'm also not sure why VKontakte survived, possibly because they became a blatant copy of Facebook as fast as they could.
Nasza Klasa (literally "our class", as in school) was crazy incompetent though. They had all social groups there - young and older kids, young adults, adults, even some elderly people - and they somehow randomly decided to focus purely on school kids, alienating everyone else. And since they were so bad at it, it became a meme, was not cool anymore and everyone left to facebook.
It's really a shame, I think it could thrive regionally until today . Big tech doesn't always win - for example also in Poland AWS tried and failed to win the market several times, because there's an existing platform that everyone uses already.
What do you mean with "as accessible"?
All the link I receive hosted by them will only show door kind of NDA or whatever you call a "click here to mindlessly accept all our ridiculous terms".
> that is as accessible as Meta'a networks are.
Meta's networks mostly inaccessible to the public. Only registered users - who IIANM are people who establish their identity vis-a-vis meta, with a phone number, or what-not - can access them.