Okay - here are some others, only those who played in the Big Ten:
Keegan Murray - Iowa: 30% 3-pt FG as a freshman, 40% as a sophomore.
Ron Harper - RU: 30% as a frosh, 35% as a soph, 31% as a junior, 40% as a senior
Terrence Shannon - as someone else posted: 26% as a frosh, 36% as soph, 38% as a junior
Boo Buie - NW: 26% as a frosh, 36% as a soph, 34% as a junior, 32% as a senior, 43%+ as a covid sr.
Roy Marble - Iowa: 27% as a frosh, 39% as a soph, 33% as a junior, 35% as a senior
Damon Santiago - RU: 24% as a junior, 44% as a senior
My point would be, that in about 20 minutes of very limited research, I found 7 players, just from the Big Ten and RU, who improved their 3-pt FG% by at least 10 percentage points, from 30% 3-pt FG, to even as low as 24%-26%, from one season to the next, many from freshman years to sophomore years.
I am NOT saying Davis (at 22% last year) will be one of those. But to say it is impossible is ridiculous. And to say it is impossible he could raise his 3-pt FG% to just 30% - which is below average, but with his other skills might allow RU to benefit greatly from his playing time - is also very close-minded, shall we say.