> the remaining piece is either to extend QED/QCD to accelerating frames of reference or to quantize general relativity

Quantum field theory in accelerating frames of reference is old hat; poster children like the Unruh effect [1] and Hawking radiation [2] are from the 1970s.

[1] https://en.wikipedia.org/wiki/Unruh_effect

[2] https://en.wikipedia.org/wiki/Hawking_radiation