

I think with Disco S1 they attempted a reset that didn’t work. They all looked the same. Nobody really liked it. So they reverted to giving them hair and there’s a throwaway line in S2 by Burnham that’s tantamount to admitting failure by the show runners. And then we don’t hear anything about it again. My guess is SNW will continue with ridged Klingons and just never explain it.
If they really wanted to go into canon, you could say there was the augment era during ENT, then they fixed their ridges with a hypospray, and then just before SNW reaches TOS times, there was a recurrence of the augment craze on Qronos. Or a COVID like virus escaped from a lab. It would be odd because all the characters we know from TOS never comment on this oddity - Spock, Kirk, Uhura have all seen ridged Klingons, then the smooth kind, and then ridged again in the movies. But stranger plot points have been ignored in Trek. Borg Queen anyone?
I think that’s my point. With PIC S2 we even get a second version of the Borgs. What’s that all about? And then dropped and never discussed again. None of it is really reconcilable. They haven’t explained it because they can’t get out of corners they write themselves into. The Klingons are just another dishonorably unfortunate corner.