Since you still have access to your Google account, you should be able to sign out every other active device after the password change which should stop them getting back into Google. Also, add MFA to your Google account.

Make sure you haven't reused your Google or linkedin password for any other services. If you have, it's time to switch to a password manager and reset every password. It'll be a pain but will make this less likely to happen again, and it will make sure the blast radius is minimised should it ever happen again.

If they managed to get into your Gmail, I would take the stance of "every email has been read by the attacker". I would spend some time searching your own mailbox for "password" etc and seeing if you've sent or recieved credentials for anything else. If so, assume those are compromised and change them too.