I know very little about ipv6, but CGNAT is Carrier Grade Network Address Translation.
NAT (Network Address Translation) is how your home router takes your one public IP address and is able to simultaneously allow your phone, your PlayStation, and your smart fridge use the internet.
CGNAT is basically the same thing expect on a much larger scale and controlled by you ISP.
Best alternative to plexamp I’ve found is Symfonium. It supports plex, jellyfin, subsonic and possibly others.
If at all possible, do not expose things like ssh, RDP, etc to the internet. Use traditional VPN or something like tail scale. Just because ssh is on a different port than normal doesnt mean an attacker couldn’t figure out that your running ssh on port 335.
Wish I had the time/energy to host this much… Currently I’m running
I’m also running Jellyfin and Navidrome, in an attempt to determine if they are good alternatives to Plex for like 6 months at this point. See comments above about time/energy.
You will own nothing and you will be happy.