It actually takes more than a full NBA season for 3pt% to stabilize. It's more like a full career in college (or 2 years for really voluminous shooters). There's a LOT of variance in it, as this whole thread indicates. Shooting stroke can also be like a golf stroke where guys just lose it for a while and slump, and also people improve over the off-seasons, or have their roles and volume (and thus difficulty of shots) dramatically increase. So really, it never stabilizes in college. Polley with the one COVID shortened year and one injury shortened year is only a little over halfway to stabilizing.
As to your likelihood of shots model, there's actually 2 variables. The skill of the shooter and the difficulty of the shot (also called shot quality). So you'd expect Akok to make 12 average difficulty shots out of 23 only 4% of the time. But he pretty much takes only in rhythm open catch and shoot 3 pointers, which are probably closer to 40-50% makes for 35% average shooters.