There are sadly a ton of ISPs that do CGNAT on a v4-only service. Smaller or newer ISPs like WISPs often do it, or ISPs for apartment blocks or student accommodation, but it's hardly limited to those.
Germany in particular has a couple of large ISPs that give you a choice of either their new platform (DS-lite = v6 + CGNATed v4) or their old platform (v4-only). That's a choice made by those ISPs... and unfortunately it's one that causes a lot of people on those ISPs to end up blaming v6 for problems caused by CGNAT.
