1. Use the latest release of MalwareBytes for Mac to remove malware/adware installed on your Mac.
Install guide: https://support.malwarebytes.com/docs/DOC-1817
Uninstall Guide: https://support.malwarebytes.com/docs/DOC-1190
The installer may ask you to allow it in Security & Privacy /System Preference. Allow it.
Click the “Scan Now” button. Once done quit Malwarebytes for Mac.
Restart the computer, relaunch Safari holding the shift key down.
Remove unknown extensions(2), reset search engine (3) and reset Homepage (4).
2. Additional steps to take if necessary.
1. Remove unknown profiles.
System Preferences > Profiles
Open System Preferences, click the “Profiles” icon ( a checkmark on a gear) .
When Profiles pane opens, select the unknown profile and click the minus button at the bottom.
2. Remove unknown extensions: https://support.apple.com/guide/safari/use-safari-extensions-sfri32508/mac
3. Reset search engine: https://support.apple.com/guide/safari/customize-your-search-ibrwe75c2a3c/mac
4. Reset Homepage. https://support.apple.com/guide/safari/set-your-homepage-ibrw1020/mac