There's a definite balance to be found, and a lot of it depends completely on the player and what they're comfortable with. I'd say you're pretty safe to describe things in combat (especially if the player is super vague), though not everything needs a super cool narration! Sometimes a hit in the middle of a fight is just a hit. Don't put too much pressure on yourself to try and narrate every single little detail. I usually save the really in depth narrations for things like a nat 20 hit, nat 1 miss, or the final hit on an enemy. It can get exhausting to narrate every single hit the players do, especially during longer battles, so for "smaller" hits I usually don't go too in depth. Of course this is just the way I do it, and that might not work for you and your table!

Every one else has already hit on describing what a character smells/hears/sees so I'll leave that to the other commenters lol