the goal is to keep it interesting
if you start intro with an aggressive chord rhythm there is nothing wrong with that on itself but when everything else comes may not be impressive, so i try to not start too aggressive or maybe reduce pressure just a little before everything else comes, so people go wow when everything else come
another thing is about giving the listener a brake
like you don't really want to listen to a 3 minutes long note of a sub bass, i love bass but 3 minutes long note is not cool so you have to try to keep things cool and interesting not to over do things
the reason i don't really like lots of ambient songs is because they may overdo something like the warm chords and that does not sound cool to me
but at the end what sounds good to me may not sound good to you so do whatever you like its just that its good to talk about things to also consider what other people like as well
chords are no must do thing
you can make songs without chords and still keep interesting harmony and all that
i would not say your song is bad just because you didn't use chords however chords can make song more interesting i always love it when i see someone used something like diminished, sus2,4, major7, minor7, chord inversions and all those can give interesting tension to the song and be interesting to listen to so i use chords all the time like pad chords, rhythm chords, fillers
so i use chords like almost all the time
but to not overdo something i may look for different sounds, sometimes more warm, sometimes more bright like strings, sometimes rhythm chords, so i try to keep bringing new things to keep it interesting, and not overdo but they are almost all the time in my harmony