Behavior blocking can be done across many IPs.

If you have one IP that scans port 10000, the other port 10001, and thousands of other IPs scanning just 1 port it’s still blatantly obvious.

And if they want to scan in a less obvious manner they need to do this spaced by days.

VPN is easier to setup securely out of the box for most especially with limited knowledge.

One of the top audit companies disagrees with you: https://blog.trailofbits.com/2016/12/12/meet-algo-the-vpn-that-works/

But then it’s blatantly obvious and you can behavior block.

Use a reputable self-hosted VPN, for example https://blog.trailofbits.com/2016/12/12/meet-algo-the-vpn-that-works/ (Trail of Bits is one of the top auditor/security company)