I posted about this before, but, at least historically, it’s a little more perception than reality. Also you forgot Ingram who vastly improved his 3-point shooting at UNC from previous years, and not entirely correct on Withers (see below), but here is part of my post from when we previously discussed this:
Brady Manek shot the best 3-point % of his career under Davis (that was the only season of his career he shot over 40%).
Harrison Ingram shot the best 3-point % of his career under Davis by about 7%.
Cormac Ryan shot the second-best 3-point % of his career under Davis (the .407 he shot two years before coming to UNC was the anomaly).
Jae’lyn Withers didn’t have a lot of 3-point attempts throughout most of his career and was very inconsistent from year to year, but his fifth year Davis gave him more of a green light and he had his best 3-point % of his career at .443 (an excellent percentage).
Not a transfer, but I believe Ian Jackson’s .395 was the second highest 3-point % any UNC freshman has shot after Kerwin Walton’s 42% (Walton’s % dropped after Davis took over for Roy, but so did his playing time). Jackson is shooting a slightly lower % this season under Pitino (.368).