I’m on it, your address is never shown, and it’s not linked to other accounts you hold. I find it useful. I just checked mine, the latest post is from Ofgen to tell you how to avoid scams from bogus energy companies.
I find it useful for local tradesmen and to date only one has let me down. I just remove the names from connect and to date only one has hassled me but he soon got the message.
I’ve been on Nextdoor for quite a while and found no problems . Nobody has tried to message me apart from a lady who bought an ebike I was selling. It’s great for local information. I think you can join using just your first name and an initial of your surname.