I do the codeword and the non cryptic crossword in the paper every day, and the general knowledge ditto when there is one. Yes, OP, I do find words that I know I know (IYSWIM) eluding me - today it was ‘white herons’ (egrets) but it came back to me. I find that if I stop trying hard to remember them, they usually do.
And I do find now with code words, that I remember rather better that e.g. 24 was M, than I did when I started doing them, some years ago now.
One thing that I do think helped ‘ze little grey cells’ was taking up the piano again (from a very low base and after a 50 year gap!) after I retired. Starting from hardly being able to sight read at all, the improvement was slow but eventually substantial - as my brain forged all those new pathways.
So that instead of seeing a simple chord on the page and having to think, Er, that’s a C and an F sharp - I would recognise and play it without having to think at all. New brain short cut from eyes to brain to fingers!