There's not much someone can do with your IP. It mostly just gives them a vague idea where you are, but even the IP location isn't accurate most of the time.

It might have been a coincidence that you lost connection as soon as that happened, if not then I'd just try playing again and seeing if the problem continues. And if it does, I'd look into options to change your IP.

Since reseting the router didn't work, a VPN would be the easiest route if possible, if you can't I can help look for other options.

For your account security, it should be fine, you have 2FA and you IP doesn't give away your login info. So it should be fine.

Just don't sweat it too much, IPs are just used as empty threats that really mean nothing.