[sn9]

I'd check out Cal Newport's work on efficient study habits and apply Anki where it makes sense.

For example, read this and follow the links: https://calnewport.com/case-study-how-i-plan-to-study-for-my...

Obviously ignore the stuff that's less relevant for an autodidact, though seriously consider the effect any particular thing could have on your learning. For example, perhaps you'd get a high ROI paying a history graduate student to assign and grade a research paper or exam.

Ali Abdaal also has great suggestions that should be useful: https://aliabdaal.com/the-essay-memorisation-framework/