I’ve never been a fast knowledge absorber, but that just meant I required a bit more time on my own, struggling with the content. Still managed to get max grades at undergrad university (didn’t go further because, well money). Also never stopped me from excelling in all work positions so far in life. If anything, a bit of struggle helps you go deep, and deep is much more valuable than fast but shallow (in my opinion).
Not professional advice, YMMV etc.
And I’m also old enough to realise that it’s starting to slowly decline and won’t be getting any better. Fluid intelligence that is. Good thing I went deep over my career, because that depth can’t be replaced by the younger set with their superior fluid intelligence. Knowledge, experience, and dare I say it, a bit of wisdom. Struggling a bit to really understand things has served me well in life.
The need to have seen something before a class to have a chance at passing it well is fundamentally wrong.