I think you might love rock climbing, esp bouldering. It’s hard on the body, but your mind is engaged like a game of chess - to be fair more like solving set chess problems, it’s so satisfying when you figure one out.
Never found a martial art as intellectual as BJJ. I usually give the same example: I doubt you could learn anything about boxing reading a book. But for sure you can expand your BJJ game reading a book (of course it's not a substitute for real training). What I mean is that there is a huge amount of of knowledge in BJJ that you can acquire, consciously, reading a book, watching a video, or listening to someone's explanation. Again, in boxing, you won't improve much your combinations just listening to an explanation on how to punch. Training is not just necessary to improve, but also to reach a minimum level of proficiency.
But even though in boxing listening to an explanation won't improve your combinations significantly, listening to an explanation on how to escape the mount (the position where your opponent is basically sitting on top of you, both knees in your armpits, ready to deliver punches or proceed with submissions) will definitely make a difference, even if you don't practice it much. If you consciously know the sequence of movements, chances are you're getting out much faster than someone who doesn't, even without the intuition that you can only achieve with continuated practice.
You can strategize at many levels, you usually have time to think (not always, obviously) about your next move, the pace is slower than in the striking martial arts, or even standing grappling martial arts. You don't need only instinct and subconscious skills, you also need hard knowledge about the technique being used.