Been listening to a lot of prog black metal and ambient black metal recently, mostly A Forest of Stars, Ihsahn, Solefald, Petrychor, Wodensthrone, Oskoreien, Vintersorg, and Solstafír (gotta have that post black metal going too lol)
that's why there are subgenres lol, that way you can nitpick. the bands I mentioned are all black metal, but are faaaaar from the traditional black metal sound.
I agree, if you say "black metal" then you should hear "Emperor" or "Immortal" in your head... if you say "progressive black metal" then you should hear some "Mirrorthrone" or new "Enslaved"
Thing is, Vintersorg never was black metal. Sure, it the some harsh vocals and tremmelo picking, but it ain't more lack than lets say...Alcest! By the way, I would never use Immortal as I prime example of black metal.