Go step by step and test.
1. Remove Adware
Run the latest release of Malwarebytes for Mac to remove malware/adware, if installed on your Mac.
For instructions: Install Malwarebytes for Mac Uninstall Malwarebytes for Mac
Click the “Scan Now” button. Once done, quit Malwarebytes for Mac.
Restart the computer and relaunch Safari holding the shift key down.
Repeat the scan couple of times.
2. Additional steps to take if necessary (1)
1. Remove unknown extensions: Safari > Preferences > Extensions
https://support.apple.com/guide/safari/use-safari-extensions-sfri32508/mac
2. Reset search engine: https://support.apple.com/guide/safari/customize-your-search-ibrwe75c2a3c/mac
3. Reset Homepage. https://support.apple.com/guide/safari/set-your-homepage-ibrw1020/mac
Please read. Ref: https://forums.malwarebytes.com/topic/236261-how-to-remove-weknow-malware-and-others/
4. Restart your Mac. Relaunch Safari holding the Shift key down.
3. Additional steps to take if necessary (2)
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 Login item.
System Preferences > Users & Groups > Login items
Authenticate and unlock the lock.
Highlight the unknown login item and click the “-“ button at the bottom left to remove it.
3. Remove unknown cookie/cache
Safari > Preferences > Privacy
“Remove stored cookies and data: Click Manage Website Data,
select one or more websites, then click Remove or Remove All
Manage cookies and website data in Safari on Mac
