The problem with college basketball is there is zero development and most of the 5* recruits honestly just wind up not being that good. I feel like it’s rare that a #1 overall kid is actually even that good in college or the pros these days.
I think one and dones are hard to deal with in general...
No matter how much talent you have, it means you need to get on campus, learn the coach's scheme, learn your defensive assignments/rotations, etc. Unless you're highly mature and intelligent, incorporating all that quickly enough to mentally be ready for the season is REALLY tough as a true freshman.
If you know you're going to be in the NBA after the season, it also gives you less motivation to really work on trying to be perfect for your college teammates too.
For Purdue, we don't really get one-and-done kids. But our highest ranked recruit, Caleb Swanigan, was a 5* and ranked #19 in the country by 247 as a recruit. He was an All-American and went into the NBA--after his SOPHOMORE season.
His freshman season he was talented enough that you couldn't keep him off the floor but raw enough that he was a turnover machine, defensive liability, and generally helped the team but also hindered it. For every 2 steps forward, he took 1.5 steps back.
It wasn't until his sophomore season that he dominated.
A lot of one-and-dones are like that... The NBA knows their potential, so they're going to get drafted high regardless of what they do in college (look at Romeo Langford, for example--didn't do much and did it on a bad team, still drafted high). But they don't always help their TEAM win during that one year in college.