I do the same, I’ve started writing my notes on the margin of the pages. I use this to go back after a period of time and easily refresh myself on what I seen as important points of the reading

I also feel that one day my kids will open those pages and can see what my perspectives were of those points in the book, as they begin to read more

I’ve tried various other methods and I just never go back to them like you’ve pointed out. Something to me about picking up the book skimming through and looking at my notes, I think it also helps give more context to the note in case you jot something short that later you don’t fully remember what your note was referencing