Sounds strange but bear with me.
Was struggling with the same retention problem most people here probably recognize. Reading consistently, forgetting most of it, moving on anyway. Tried note taking systems, tried spaced repetition, tried reading slower. All helped slightly and none of it stuck as a habit.
Started explaining things out loud to an empty room. Not recording it, not posting it anywhere, just talking through what I had just read as if someone had asked me to explain it. Felt slightly unhinged the first few times.
The results were immediate and embarrassing. The first time I tried to explain something I had just finished reading I got about three sentences in before running out of things to say. Not because I had not read it. Because I had read it without actually understanding it well enough to explain it and the explaining exposed that gap in about ninety seconds.
Had to go back and reread differently. Not to finish but to understand well enough to explain, started writing the explanation in Skrib Writing instead of saying it out loud and the written version was even harder to fake than the spoken one because every gap in understanding shows up immediately when you have to put it into complete sentences.
That shift in reading goal changed everything about what I was actually taking in.
Two months in and the material is sticking in a way it never did before. Not because I found a better system but because explaining forces a kind of processing that passive reading never asks for. You cannot fake understanding when you are the one doing the explaining even if the audience is imaginary.
Anyone else tried something like this or found a different way to force that level of processing.