I am also one of those "always good" players. But definitely Chaotic Good. I don't recall ever playing a strictly evil playthrough in any game, some choices here or there might have been "the lesser evil" as some others have described it.
I'm not really worried that this won't be possible in BG3, just maybe a tad apprehensive that Larian got a bit carried away with designing the "evil" stuff and we will end up feeling shortchanged. We'll have to wait and see.. hehe

I'm really curious how the upcoming iteration of Pathfinder 2e will play out, cause they will get rid of alignment completely (iirc). Is something similar planned for OneD&D (or whatever they call it)? Does anybody know?