So if a normal non-holding back Superman ripped a more powerful than ever (in the Nu52) Doomsday apart. How powerful and what Tier would a sun-amped not holding back Superman be in? It is hard to say at this point, but what would you speculate?
You can put Superman everywhere from mid herald to skyfather. That was always the case, it always depends on the story, with things like the CA he is even Omniversal. An sunamped Superman was pre-flashpoint able to compete with the energies of an Universal being. I would say that NU Supes is at HH levels most of the time, when not holding back in the Trans tier and with an sunamped beyond.