@ledoian Uh. AS50825, IPv6 /48 from 2a03:c20::/29, for extra fee they have legacy IP from idk what. They are able to make NS record for »reverse DNS« if you ask nicely.
They are willing to debug network issues a and actually try to fix them, I had great convo with their techs because CETIN eating PTB, we exchanged tcpdumps, and then they contacted CETIN (that issue happened all over CETIN's network).
I know some server of theirs runs outdated unsupported Fedora.
Wouldn't be sure about BGP (did not ask), but in that case I think if it won't be possible, then it is on CETIN. I know someone who works there, so I could probably ask personally on some things. My »coworker« (different team, different city) used to work for them and claimed they actually like went around conferences and were reading RFCs and stuff to actually implement IPv6 properly.