The physics of today acknowledges that our scientific explanations for Mechanics and Electromagnetism are complete. No longer will there be an observation that caused us to re-think these two fields of study. Look it up. Innovations abound and will continue to change our lives.
The physics of today acknowledges that general relativity and quantum mechanics are fields of study that need further work since some measurements disagree with predictions (but most do). GR and QE provide incredibly accurate descriptions for the natural world. The physics of tomorrow will continue to build on this incredible knowledge base, keeping models that predict our observations and ditching the ones that don’t.
But.....science will never be able to uncover "the thing-in-itself" since we do not have quantifiable observations of it.
I guess you could say the same thing about dark matter. We are actively searching for and modeling dark matter. As yet, there is no consensus. Since we can measure its effects (expansion of the universe, explanations for the rotation of galaxies, etc...), we’re certain that we’ll eventually find clues for its nature. Then modeling can put the observations in context with known physics. May need new physics. This is the nature and the extent of scientific endeavor.
What bothers physicists the most can be put into a phrase that Donald Rumsfeld (US secretary of Defense, 2000ish) created.
I paraphrase:
"I am not concerned with the known unknowns, I am most concerned with the unknown unknowns".
I am not fond of this man's accomplishments, but he was right on with this one. Physicists sweat in their sleep over this one.

