Virus after upgrade to Ventura

I upgraded to Ventura one week ago (from Monterey). When I open my MacBook Air I always have a small "zestradar.com" window in the right upper corner. It disappears after a few seconds. Today I have in the same position a "Security Advisor" window that does not disappear... Windows are always asking "click here to get more info"...Virus??? Phishing??? I use Malwarebytes and CleanMyMac: both congratulate me all the time because "I am clean". Pfff...I am clean since I was born, but my laptop is not any more since I upgraded!!!