Hi @lasttime,
Some things to try.
Download, install and run the following 2 apps to check for any viruses and malware, [https://www.avast.com/en-au/free-mobile-security|App 1], [https://play.google.com/store/apps/details?id=org.malwarebytes.antimalware&hl=en|App 2]
Turn off Bluetooth if not you’re not using it to guard against any unauthorized access.
Only if you want to, [https://support.google.com/accounts/answer/32046?hl=en#:~:text=Go%20to%20myaccount.google.com,a%20service%20or%20your%20account.|cancel your Google account] and create a new account, email etc, one where the account details are ''known'' ''only to you''. (Memorize them as you may need them in the future if you have to reset the phone etc).
Here’s a [http://motorola-global-en-roe.custhelp.com/app/answers/detail/a_id/137583/~/user-guide-%28html%29---moto-g7-play|link] how to remove the account details from the phone.