Can anyone do any damage to your phone if they have your imei/Meid number?
Depends where you are but they can report it stolen and block it here.
That is why it’s important to have a passcode and faceid. I always keep my phone on me as well. I don’t let it out of sight
Glad I asked, someone who said they could fix my phone asked me for it and I wasn’t sure what that number does.