D&D is one of the systems which most easily and repeatedly turns to farce, in my experience. I think this is largely because of the high chance of just outright failure on most rolls due to the d20 RNG and total lack of degree of success, together with some inherently silly rules and concepts (falling lol particularly).
When I picked up Dungeon World, which is basically a D&D vibes PtbA game, I assumed it would be less serious than D&D, but every time I've run it, it's gone way more seriously (Conan on this list).
If it was up to me, when I run/play D&D it'd be at LotR level, but in reality it never fails to be GotG level.