Depending on your technical level and your privacy preferences:

Robosats is a peer-to-peer exchange that runs over Tor, and is one of the most private ways to buy Bitcoin (ie you’re not tying your identity to every transaction you make, or making your net worth known)

I believe nostr:npub1ex7mdykw786qxvmtuls208uyxmn0hse95rfwsarvfde5yg6wy7jq6qvyt9 is now available in Europe. It’s an excellent way to stack Bitcoin, with an ethical company, but like most exchanges requires KYC and reduces privacy. Not sure if nostr:npub1cashappn03s3cl2ljsdntv0v28e2um5lgx4vjctqjt23pcwzjhsqmtdg5l is in Europe yet, but same thing. Also nostr:npub15369wu3wzzar5fclhecyqfv683x69n6nhlg7rxqnsg2dydgxflpq3apswl is a European app, peer to peer, which appears to be extremely user-friendly.

Hope this helps 🫡