Spaced repetition systems have gotten better

I find with spaced repetition that it works really well for some well-known things like vocabulary (EDIT: well-known meant as "spaced repetition is well-known to work for this use-case, not well-known as "the subject is well understood"), medical etc. but for everything else it becomes a struggle for a long time.

I have been trying for years to fined a way to use it for mathematics and physics - with the former being more of a focus and didn't really get anywhere. For definitions it works, but it's quite hard to write proofs in a way where there is a short obvious memorization based answer. Either you spend far too much time on a card or the card gives you too much information so you don't really test the knowledge.

I also tried it for computer shortcuts - it seems to me that they are really useful only when part of the muscle memory - so practicing them works better then memorization.