[jeroenhd]

All of the NAT problems would instantly to away with IPv6, but with adoption still at a meager 50% I suppose you'll need a PBX of some kind to receive at least half the calls.

For those stuck behind CGNAT, there are guides online for how to set up a VPN to a cheap VPS and forward all network traffic to your network so you can have almost-real connectivity at home. If you're content with 50mbps, you can even use Oracle's Always Free tier.