I setup my opnsense firewall for IPv6 recently with Spectrum as an ISP. I followed this howto from The Other Site:

https://www.reddit.com/r/OPNsenseFirewall/comments/xmurda/psa_howto_ipv6_on_spectrum_formerly_twc_time/

Even as someone who has a background in networking, I'd have no idea how to figure some of that stuff out on my own (besides reading a whole lot and trying shit that will probably break my network for a weekend). And whatever else you might say about Spectrum, they have one of the saner ways to implement it; no 6to4 or PPPoEv6 or any of that nonsense.

I did set the config for a /54, but Spectrum still gave me a /64. Which you can't subnet in IPv6. Boo.

Oh, and I'm not 100% sure if the prefix is static or not. There's no good reason that it should change, except to make self-hosting more difficult, but I have a feeling I'll see it change at some point.

So basically, if this is confusing and limiting for power users, how are average home users supposed to do it?

There are some standardization things that could make things easier, but ISPs seem to be doing everything they can to make this as painful as possible. Which is to their own detriment. Sticking to IPv4 makes their networks more expensive, less reliable, and slower.