At this point, it's getting hard to say that Domas isn't at least a pretty good rim protector. He's allowing 56.4% on shots at the rim this season. That isn't an "elite" figure, but when factoring for volume, it's rather impressive. Domas has defended a total of 225 shots at the rim so far this season, which is the top mark in the entire NBA.
For comparison's sake, Nikola Jokic has defended 205 shots at the rim so far this season, while allowing a gaudy 67.8% on those shots. Brook Lopez is currently the best rim protector in the league, having defended 216 shots at the rim, while allowing only 52.8% on those shots.
https://www.nba.com/stats/players/defensive-impact?PerMode=Totals&dir=D&sort=DEF_RIM_FGA
So yes, while Sabonis is certainly not a DPOY candidate, he's actually a much stronger rim protector than many would imagine, particularly when accounting for volume.