see the mess of a priori causality conditions and chronology protection conjectures in GR

Classical GR actually rules out changing the past (while allowing CTCs), despite the common misconceptions about it. The Novikov's self-consistency principle was self-admittedly a way to say "there is no new physics other than GR". Hawking's famous chronology protection paper mainly showed that QFT cannot be done in the standard way on a wormhole background.

Tachyons are declared unphysical for similar reasons.

They are generally "declared unphysical" because the time-travel aspects cannot be analyzed self-consistently. Plus there is little evidence for it. However, non-propagating tachyon fields are not incompatible with GR. For example, a 2+1D slice of a 3+1D Schwarzschild black hole contains induced FTL matter fields, Kaluza-Klein style. PM me if you want more details.

So-called retrocausal interpretations of quantum mechanics

I can't imagine how an interpretation can be a promising research topic.

There is still a big unwritten assumption in theoretical physics that proper scientific explanations must account for things that happen now in terms of things that happened earlier. I can't think of any reason for this bias beyond an attachment to causal narratives.

I think this is overstating it. As long as a model is capable of predicting future observations based on the current ones, it is worth considering. If not, then it's no longer a natural science, but at best math.