you need to understand how nostr works

we sign messages with encryption and thats basically it, how and what messages we get and many other beautiful things are being worked out, but the basic principle is signed messages where you own the keys not someone else

those messages once signed are free to go anywhere, and via the wonder of math we can know who signed it

you own your id on nostr not someone else, each message is provable to belong to someone, you dont need any server to prove anything