I understand your point because he is quieter than most, but it is not
nothing. He does grunt on
all serves, and on a fair amount of topspin forehands. The footage on TV isn't reflective of the noise he does make, and everyone should emulate his level of exhaling/grunting imo, which is just the right amount to aid performance but not upset the opponent. From the other end you wouldn't or shouldn't notice and it is certainly not an issue for nearby courts.
To my mind the takeaway is that even Fed grunts on every serve so that is OK. Sabalenka on the other hand has a major issue, but because no-one is willing to do anything about THAT, you will always see players on the tour replicating it. When your grunt is still audible as the opponent is hitting the ball, there is absolutely no way that aspect (length of the grunt) wasn't trained. By whom or when, I have no clue.
Then you are in accordance with one of the greatest players ever!