I've been musing over this topic for awhile, even thought about posting something similar, but the OP did a much better job than the rambling I would have done.
I don't *need* an explanation for the changes of appearances for the Klingons to enjoy the story, but it is kind of fun to come up with some headcanon ideas to reconcile the changes.
I kind of take an "all of the above" approach. I think there's been some interbreeding among Klingons and the various races they've conquered. I think there's even been some interbreeding between augmented Klingons and unaffected Klingons (General Chang?). I've also considered the idea that maybe the Klingons we saw in DSC are 'pure' Klingons with no mixed heritage, and all the others we saw up to this point had some mixed heritage and/or traces of the augment virus. I mean, if you took a DSC Klingon and mixed it with an augmented Klingon, you'd get something that looks like the Klingons from The Search For Spock and onward.
I don't *need* an explanation for the changes of appearances for the Klingons to enjoy the story, but it is kind of fun to come up with some headcanon ideas to reconcile the changes.
I kind of take an "all of the above" approach. I think there's been some interbreeding among Klingons and the various races they've conquered. I think there's even been some interbreeding between augmented Klingons and unaffected Klingons (General Chang?). I've also considered the idea that maybe the Klingons we saw in DSC are 'pure' Klingons with no mixed heritage, and all the others we saw up to this point had some mixed heritage and/or traces of the augment virus. I mean, if you took a DSC Klingon and mixed it with an augmented Klingon, you'd get something that looks like the Klingons from The Search For Spock and onward.