I haven't made any assumptions about your goals. I simply reminded you that memories kind of have "expiry dates", so that review dates are necessary. The backlog you mentioned is the memories you're about to forget if not "refreshed" in time. If you just want to practice whenever you feel like it, there are tons of apps that use a simple Leitner box, but you may soon find that it becomes a burden to review your cards if you add an important amount of them. Anki already has ways to do what you want, while still working according to your memory patterns, such as using filtered decks and lowering desired retention.
I already pointed out twice that Anki doesn't work for me, and your response is basically still 'you're holding it wrong'. I know of all the things you mentioned, and like I said, they didn't work for me, which is why I was looking for recommendations (which other posters have provided).
The point is that you're looking for something that accounts for your memory patterns while reviewing things haphazardly, which goes against the former. It doesn't exist. I wonder why you just don't use traditional study methods at this point. If you dread the backlog (and you shouldn't if you have well formatted cards, which may be why it didn't work for you) you will dread the alternative even more.
> I wonder why you just don't use traditional study methods at this point.
Because I'm not a student. Why is it so hard to accept that I know what I want and am just looking for recommendations that do that? If they don't exist, so be it. The point of my question was to find out what exists, not to get a lecture on what I should want.