I HAVE heard of someone that runs SSH on port 443 and HTTPS on 22.

It blocks a lot of bots, but I feel like just running on a high port number (10,000+) would likely do better.

I have a service running on a high port number on just a straight IPv4 and it does get a bit of bot traffic, but they are generally easy to filter out when looking at logs (well behaved ones have a domain in their User-Agent and bingbot takes my robots.txt into account. I dont think I've seen the Google crawler. Other bots can generally be worked out as anything that didn't request my manifest.json a few seconds after loading the main page)