IPv6 support in 2025?

2025 and still the same prefix delegation issue that has been here for over a decade now.  I've moved around a few different places over the past 10 years, and anywhere I've had xfinity I've run into the prefix delegation issue *only* on xfinity.  This is with a combination of xfinity-provided modems + a variety of routers.  None of the other ISPs I've used have *some* ipv6 support (they either flat out do not support ipv6 at all, or they support it correctly and I've been able to get ipv6 working on many of my routers without issue).  

I've called a few times over the past decade to ask why prefix delegation doesn't work properly, and of course the first-line customer service agents have zero clue what I'm talking about and push back about it being a configuration issue on my router (not to mention now you have to wade through the "smart" agent AI that answers first...but that's an entirely different story).

TL;DR:  tired of xfinity saying they support ipv6 when they don't (not properly, at least).  When a router solicits an ipv6 delegation, it should be able to get it.  Otherwise, ipv6 (SLAAC, RAs, etc..) wouldn't work.

For reference, here's the latest response (20 minutes ago in zip 71118) I get from xfinity when requesting an ipv6 prefix:

parse_ia_pd_options: NoPrefixAvail - Server support for prefix delegation is not enabled.

AT&T just rolled out 5Gbps synch fiber in my area.  As soon as that's set up at my location, I'm dropping xfinity.  At best, they'll support ipv6 correctly.  At worst, my ipv4 will at least be 4x faster with a ton more upload speed.

Cheers.