I think the basis of a very cool ambient song are there. Personally I totally suck at creating synth based percussions so I can only tip my head for those.
Overall the synths sounds interesting and I think the building blocks for creating a big and cool ambience are there. However I feel there is so much that could have been done with. Create larger ambience with, by utilizing the stereo field more and by using effects like EQ and reverb more, to craft those sounds that surrounds the listener. Also creating more darker or deeper sound to broaden the frequency spectrum more. Also, sadly the playing leaves something to be desired, while it sounds ok for most of the time, the lead melody just feel off by a lot.
Nonetheless. You still made a cool sounding song and created this with your own synths. You should still be proud of your work 😊