I tried it last night on my 3080. Yes, it looked nice... for 10 seconds, and then I really never noticed it again. I'm sure it's not implemented fully like in Metro Exodus, thus you're still seeing traditional fake lighting and shadow effects, with some RTX overlayed - mostly reflections in shiny surfaces it seems. But this is something you're just not going to notice in a fast paced FPS game.

RTX, or ray tracing in general, is just one more item in the graphics toolbelt. Yes it will make games subtly look more immersive and realistic, and if a game is written ground up for it, it could lead to very interesting and spooky environments. But like most SINGLE graphics features, by itself it doesn't make a startling difference, especially in a game like Doom Eternal, that wasn't made for it.

About the only game that I think really looks noticeably better with RTX is Control, and that wasn't even build from the ground up for it, but it makes very effective use of ray tracing in the creepy environments, and you walk through that game slow enough to appreciate it.

Honestly, I didn't buy a 3080 for RTX. I bought it to play the games I love at Ultra with better framerates than my old 1080. No one should buy a 3000 series card just for RTX.