Some of the best ambient ever made uses little or no drums/percussion.
Certainly, on the question of ‘drums/percussion vs no drums/percussion’, ‘ambient’ as a genre, is much closer to the ‘no drums’ side of things.
Obviously, ambient and chill are not exactly the same, but they’re not dissimilar. Good chill can use drums/percussion very sparingly; barely there.
Bass is really important to give the track a good foundation. Soft bass, though.
You can have epicness in ambient too, where more aggressive basses can fit perfectly.
It’s worth checking out the series of compilations ‘A Brief History of Ambient’ to hear a good spectrum of ambient (and some more rhythmic) music; from the floaty and light to the dark and aggressive.
I think I made a pretty decent example of how a more aggressive bass can work in ambient in a piece from a short while ago…
Fwiw, no drums and only a single percussion sound, iirc.