So I dont think this paints the complete picture, but here we go!
I will omit 2016 (good grief that's a long time ago haha)
Oct 19th 2020 (L 17-26): Klein is filling in for Milano and has 88% of DEF SNAPS: (7 tackles, 1 FF) (Tgt 4 times, only 1 completion allowed, 0 Passes Deflected)
Jan 24th 2021 (L 38-24): Klein gets 7 Def Snaps (no stats), (a missed tackle somewhere either D or ST)
Oct 10th 2021 (W 38-20): Klein again in for Milano and has 63% of DEF SNAPS: (9 tackles) (Tgt 8 times, 6 completions, 0 Pass Def)
13 Seconds: NO defensive snaps
I'm not sure what to make of it, the one game they get 6 completions off of him, the team wins by 18, so who knows if that includes some garbage time catches?
Just pure eye balls, he seems to play hard, but doesnt have the twitch like the others. However it seems like AJ also knows this too and (again going off memory) probably plays very fundamentally sound.