I'm not convinced, the Nothing Ear spatial audio effect (which is pure postprocessing as far as I understand, since it's independent of codecs and containers) sounds a lot more realistic, and I doubt Nothing has the best algorithm in the field
As for the effect, I was trying to get a particular effect I'd liked using earlier, rather than the most realistic spatial audio algorithm. The earwax effect mentioned elsewhere in the thread also sounds quite close to what I wanted. Posting this also worked as discovery, getting me some good suggestions for other effects to reverse engineer.