Move it to a four digit port on your router and port for to 22 internally.

Noip $25/year

That depends on the port/service you’re forwarding.

It also depends on your ISP if they filter some standard ports.

Non-standard ports can obfuscate your service, prevents it from being detected by crawlers and bots.

Start small and don’t ignore security standards.

Patch your stuff. Use common sense.