Check for adware.
Run the latest release of Malwarebytes for Mac to remove malware/adware, if installed on your Mac.
For instructions: Install Malwarebytes for Mac v4 Uninstall Malwarebytes for Mac
Click the “FREE DOWNLOAD” button.
Click the “Scan” button. Once done, quit Malwarebytes for Mac.
Restart the computer.
Scan for Malware again.
About malware:
If you think that you might have malware or adware on your Mac, update to the latest version of macOS. If your Mac is already running the latest version, restart it. macOS includes a built-in tool that removes known malware when you restart your Mac.
https://support.apple.com/en-us/HT204296
Safely open apps on your Mac
https://support.apple.com/en-us/HT202491
What is malware
https://support.apple.com/guide/mac-help/what-is-malware-on-mac-mh27449/11.0/mac/11.0
Reboot the Mac
Malware Removal Tool
Should malware make its way onto a Mac, macOS also includes technology to remediate infections. The Malware Removal Tool (MRT) is an engine in macOS that remediates infections based on updates automatically delivered from Apple (as part of automatic updates of system data files and security updates). MRT removes malware upon receiving updated information, and it continues to check for infections on restart and login. MRT doesn’t automatically reboot the Mac.
https://support.apple.com/guide/security/protecting-app-access-to-user-data-secc01781f46/1/web/1
https://support.apple.com/guide/mac-help/protect-your-mac-from-malware-mh40596/11.0/mac/11.0