I don't have anything for this season, but RJ Barrett hit 43.5 percent of his threes after the All-Star Game in 2020-21.

rj barrett 3 point percentage since allstar break
Interpreted as:
RJ Barrett 3 point percentage since allstar break this season
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NAMESEASONTMGP3P%MPGPPGRPGAPGSPGBPGTPGFGMFGAFG%3PM3PAFTMFTAFT%MINPTSREBASTSTLBLKTOVPF+/-
RJ BarrettRJ Barrett2020-21NYKNYK3543.536.718.65.53.10.80.32.06.715.343.82.35.32.93.976.31,28465219310829126992+93
StatMuse has game-level data for three-point percentage going back to the 1983-84 season.