Let's look at Hamilton and Purvis at UConn vs G-League stats:
Hamilton
UConn: 31.7 mpg, 11.7 ppg, 8.9 rpg, 4.7 apg, 2.4 TO/g, Assists/TO: 1.96, 38.4% FG, 33.7% 3Pt, 77.2% FT
GLeague: 32 mpg, 15.6 ppg, 8.3 rpg, 5.3 apg, 3.4 TO/g, Assists/TO: 1.56, 43.9% FG, 37.3% 3Pt, 77.9% FT
Purvis
UConn: 31.4 mpg, 12.8 ppg, 3.2 rpg, 1.9 apg, 1.7 TO/g, Assists/TO: 1.12, 41.0% FG, 36.0% 3Pt, 67.6% FT
GLeague: 38.5 mpg, 21.3 ppg, 3.9 rpg, 2.6 apg, 2.5 TO/g, Assists/TO: 1.08, 44.8% FG, 38.1% 3Pt, 84.6% FT
Now let's compare them to the average G-League player:
Average in G-League: 45.6% FG, 35.3% 3Pt, Assists/TO = 1.16
Hamilton and Purvis seem to be similar players in the G-League as they were at UConn, but both are scoring more as G-League games are generally higher scoring than college games as the G-League averages ~110 points per game. Hamilton is shooting better in the G-League and doing all of the other things like rebound and assist that he did at UConn. Purvis is shooting slightly better, rebounding about the same, and his assist/TO ratio still hovers around 1. Both players are shooting below the average G-League player, but both are shooting above the 3Pt% average. Hamilton is above average assists/TO and Purvis is below average on assists/TO.
By the way, both Hamilton and Purvis would have 100+ G-League players with higher 3Pt%, including Roscoe Smith and DeAndre Daniels.
We can debate if Ollie is a good coach or not, but Hamilton and Purvis are performing similar to the players they were at UConn in a more wide open game. I would expect their shooting percentages to improve as they focus full time on basketball.