Yeah, not arguing that, it doesn’t cost them extra to allow those. Still, you can use 8080, 8989, 5000, 7878 etc, for plex, Jellyfin, nextcloud and so on.
You can even workaround it by using cloudflare functions that forward requests to your specific port, DNS it to cloudflare and run a commercial webapp out of your garage anyway.*
*Except if you want to honor whatever ToS they had you agree to.
I started using docker myself for stuff at home and I really liked it. You can create a setup that’s easy to reproduce or just download.
Easy to manage via docker CLI, one liner to run on startup unless stopped, tons of stuff made for docker becomes available. For non docker things you can always login to the container.
Tasks such as running, updating, stopping, listing active servers, finding out what ports are being used and automation are all easy imo.
You probably have something else you use for some/all of these tasks but docker makes all this available to non-sysadmin people and even has GUI for people who like clicking their mouse.
I think next time you find something that provides a docker compose file you should try it. :)