Lyxen
Great Old One
I think there's an open question as to how many groups are even interested in any conflict that isn't Good vs Evil though.
It's a good question, but actually I think that a lot of the more mature players are bored with good vs. evil.
I mean, I can't say if you're right or wrong re: how many directions you can get out of the Great Wheel, but I do think, based on the 30+ years I've spent playing and talking about RPGs that, when it comes to cosmic conflicts, people are really only interested in two of them:
1) Our team vs their team. Which doesn't require any alignments. You see this in a lot of RPGs, whether morally ambiguous or not. Team Camarilla vs Team Sabbat. Team Solar vs Team All The Other Ones (but particularly Dragonblooded). Team Wyld vs Team Weaver.
Of course it all depends on the theme of the TTRPG. Most of them are not concerned with epic, cosmic conflict.
2) Good vs Evil. Hopefully self-explanatory. This can genuinely be a bit more than a "team" conflict and provoke some more real thought.
Not my experience, actually. Our groups are a bit bored with the Good vs. Evil, which has been done time and time again.
Law vs Chaos, for example, is very interesting in Moorcock's writing and it is a reoccuring theme in literature through the ages, whether Nomos and Physis in classical Greece (technically more "Nurture vs Nature" but often used in a de facto Law vs Chaos way), or the Lintons and the Earnshaws in Wuthering Heights, and hell, you could argue it's part of stuff like The Secret History. But in games? Are many players into that? My experience is "Definitely not". People will do "Team Law vs Team Chaos", but that's just team stuff, they're not actually engaging with the concepts or particularly thoughtful about it. And more esoteric concepts than those? Either it goes to team stuff or people get bored pretty quickly in my experience (as a player and DM).
Again, no my experience, we have hearty discussion of Law vs. Chaos and what it means, or about the derivations of that, because most of our campaigns drift in the Planescape view at mid+ level and it's as fundamental as Good vs. Evil.
So maybe it's actually just irrelevant to most groups? I mean, I think there's a reason Planescape created all the Factions, more concrete "teams" for people to be part of and cheer for, rather than focusing on what might have been more obvious - the alignments of the PCs involved. The Great Wheel offer a lot of cosmic conflict, but it's not terribly engaging/valuable.
I think it's a bit different there. Planescape is also meant to be played including at low levels, and having patrons more "earthy" than cosmic principles helped. Moreover, most of the factions certainly have a strong alignment bias.
Re: Law I actually think one of the most interesting conflicts is "The Rule of Law vs. Natural Justice" (essentially LN vs NG), but it's one difficult to do well in an RPG, or to get a lot of player buy-in for.
Again, I suppose it depends on your groups, but we've always found that Law vs. Chaos resonated very strongly for us, and allowed some moral ambiguity (Good / Evil) about the means employed by the factions.