There are advanced stats, though - in particular Box +/-, which can be broken down on both sides of the ball.
Amida's current defensive box +/- is +9.7. As a freshman it was +9.6, and last year it was +7.4.
For reference:
Skal Labissiere, the presumptive first center off the board next year, has defensive box +/- of +5.4
Karl Anthony Towns's last year was +10.8, as was Anthony Davis's in his lone college season
Jahlil Okafor's was +4.1
Octavius Ellis's is +6.5
Markus Kennedy's is +6.9
Of the other bigs on UConn, Face is +6.0, Miller is +4.1, Nolan is +1.1 and Enoch is -0.3.
BPM isn't a perfect metric (I think RAPM is better, but can't find it for college) but it's really, really good. Amida has some very obvious flaws, but for the past three years we've pretty clearly been a much better team when he's out there. Let's hope he continues to improve.
(And for those of you who think he hasn't improved: His defensive rebound rate his first year was 11.1, last year was 10.8 and this year is 15.9%. That's far from elite, but he's getting better)