There are even plenty of questions, like the delayed-choice quantum eraser, that have already been solved
No, it has not been solved. At least not solved to the satisfaction of many physicists.
In one respect, there is nothing to solve. Everyone agrees on what you would observe in this experiment. The observations agree with what quantum equations predict. So you could stop there, and there would be no problem.
The problem arises when physicists want to assign meaning to quantum equations, to develop a human intuition. But so far every attempt to do so is flawed.
For example, the quantum eraser experiment produces results that are counterintuitive to one interpretation of quantum mechanics. Sabine’s “solution” is to use a different interpretation instead. But her interpretation introduces so many counterintuitive results for other experiments that most physicists still prefer the interpretation that can’t explain the quantum eraser. Which is why they still think about it.
In the end, choosing a particular interpretation amounts to choosing not if, but how QM will violate ordinary intuition. Sabine doesn’t actually solve this fundamental problem in her video. And since QM predictions are the same regardless of the interpretation, there is no correct choice.