Only the 4th point is really true: if you run SSH on a non-standard port but it's otherwise accessible, you'll still see scans on a regular basis.

Port knocking isn't a terrible idea but I generally prefer locking down the networks (or, these days, using AWS SSM / GCP IAP to avoid listening publicly at all) since having something on the internet means you're just one mistake away from problems and need to staff monitoring accordingly.

The other thing to remember here is that we're talking about one general CVE in two decades. Almost any other running service has been much worse so while SSH is important to protect I don't know that I'd make the argument that further pushing that one service is really the best bang for your buck.