When you clean using mineral spirits, did you shake it up, or flip it or both? I prefer a longer soak, but we’re talking like 15-20 minutes total time, but I don’t think that’s the issue. When I remove a bearing, it goes onto a paper towel for a bit(less than a minute), then flipped to get the other side, then spun for 2 minutes by hand on the top of a pen or pencil while being hit with a few blasts of compressed air. I don’t really let it “air dry”.
After you’re done, do you lube or you in the dry bearing camp? I wont go there, you know your preferences and the arguments for and against lube or dry running.
I’m sure you did the typical “check the bearing seat” stuff.
Lastly, just for the heck of it, have you tried the swapping then bearings from a different yoyo that is dead unresponsive? I’m just trying to isolate things. If the bearing acts the same regardless, it’s the bearing. See where the problem follows. Also, use a Sharpie to put a dot or mark on the bearings to keep track of them. All bearings look very similar at a glance, so do what you can to keep things straight. You have to isolate the problem. But I’m basing this on doing audio. I had a pair of bad cables last night setting for a gig, so I had my crew swap it out. I can always test the cable later. New cables resolved the problem.
Narrow it down. Swap bearings with KNOWN working bearings. Once yo start swapping parts around, you should be able t find the problem.