Yea, this same ISP just rolled out CGNAT without forewarning one day as I tried to make sense of why my servers (that I have colo'ed at a location with this internet service) became unreachable, yet, was still "online". I saw the router being assigned an IP address in the 100.64.0.0/10 address space, which was clear enough evidence that they stuffed everything behind CGNAT. They botched it so bad, that this is apparently what a speed test came back with (image attached).
I've moved my stuff to a different network. Yet, in the chaos of this mess, anything I had on Tor stayed online without any issue, even in moving networks (since of course an onion address isn't dependent on network location). It's just getting stupid with trying to host some things on the regular internet at this point.
(Also to be clear, the "you don't need IPv6" was sarcastic)