Phishing message in Safari

No, all such messages are scams. Close the offending page and avoid sites that are involved in such bogus advertising tactics.

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Phony "tech support" / "ransomware" popup… - Apple Community

Nope.

Scam.

If this were even remotely possible, the entire Internet would be afire.

Has a pop-up ever been anything but a sketchy product or a scam?

I routinely get these, sometimes including some of my old passwords from server breaches. (Re-using passwords is Bad.)

Here are some links to related info >

Scam Pop-ups, Scam Viruses, Scam Receipts… - Apple Community

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support