You could try the free version (as I've in my macs) of Malwarebytes for Mac;
reduced version of Malwarebytes will still work after an introductory feature.
(A free download comes with "14-day premium trial" then continues working.)
• Malwarebytes for Mac -- Mac Antivirus Replacement | Malwarebytes
https://www.malwarebytes.com/mac/
Another item to have and use (also innovated originally by contributor to ASC)
is EtreCheck. ~ This can generate a report, to post in your reply, in addition also
can be used to remove adware and malware bits.
• Using EtreCheck to Troubleshoot Potential Mac Issues - Apple Community
https://discussions.apple.com/docs/DOC-250000632
These items are often suggested and recommended above others in ASC, because
they do what they're supposed to. Each has a paid version; but initially work anyway.