Most ISPs that do use CGNAT also offer ipv6 in Australia at least. The problem is that there is always that one client network that only supports ipv4 so you end up needing to support dual stack one way or another. Most of these ISPs also support CGNAT opt out for free at least, but I suspect that will go away in the medium term (and maybe that will encourage more universal ipv6 rollout).
It’s probably a TOS violation but you can combine it with pinchflat to strip ads and sponsored content from YouTube. It’s not a general YouTube app though, rather you use it to preserve channels you’re interested in.
You can also use Jellyfin to serve legally purchased music from bandcamp etc, or movies and TV shows ripped from Blurays and DVDs.
I think you need Bazzite in your life (or some other immutable distro). But hey, fucking things up and recovering from it is how I learned both Windows and then Linux so there are upsides.
This sort of setup is a bit more advanced since it requires static routes on the remote router at least. Doable with one or two networks, but not if you have a bunch of users.