Agree. In Lovecraft’s hands, I regard it as maybe the most-honest and -accurate depiction of cosmic reality—of that horror-adjacent feeling one may experience trying to actually imagine the universe—in fiction, but the effect falls apart if you start filling in the gaps. Most of the broader “mythos” stuff since Lovecraft can still be fun in about the same way that Catholic mythology’s fertile ground for horror, but it’s not the same thing and it’s not as interesting.