Yeah, here in Russia the ISPs and IT infrastructure guys seem to be treating IPv6 like it has cooties. I can't find an article (and it'd be in russian anyway) but as far back as 2022, if you get IPv6 you can expect a variety of issues with it, ranging from "you need to reboot your router every once in a while" to "you technically have v6 but good luck actually browsing v6 internet".
And of course, why would they give you a stable IP when they can charge for it :T. At least it's only a third the price of a stable IPv4.
My current ISP technically provides v6 according to their site - but my connection doesn't have it, and since there's nothing about it in the years-old contract, I'd need to redo that if I want to complain.
There are usually plenty of choices for ISPs here, actually. But switching between them isn't likely to give me IPv6 since either they share a magistral or the hardware is just plain old. That, and IPv6 is just not a thing anyone markets.
...and with the current fuckery going on, I doubt many of them have budget for big upgrades. Or maybe even access to hardware to buy.