Backwards time travel or FTL are not measure of progress. Even with the field of "fundamental" physics:
1. There are lots of things we do not understand in cosmology (cosmological constant, nature of dark matter, matter/antimatter asymmetry, force unification at very high energy scales, gravity at high energies, etc). Each of those could potentially revolutionize our understanding of the universe
2. There are lots of things we do not understand at small scales (Casimir effect/vacuum energy relationship, plank scale effects, why the particle soup, gravity on very small scale, reason behind asymmetry in helicity/weak interaction and other parity/symmetry related effects, doing "useful" calculation with renormalization group, etc). Each of those could potentially revolutionize our understanding of the universe.
There is also a lot to be done in our understanding of computing (as in, nature of computation)
1. Computation related problems (Church-Turing thesis, novel algorithmics + computing platforms such as quantum computing). Is approximately correct/probabilistic computing a loophole for getting essentially/mostly correct results in P time for NP-hard problems? Nature of AGI/what enables sapience when doing computing.
Of course as we go into "less fundamental" sciences like chemistry/biology/etc then the amount to be learned is just overwhelming, we truly know very little.