this is really good to be honest... I think you can add more though, maybe adding a few more things to the drums as the song progresses, some more atmospheric elements too ( maybe some vocals with reverb, but you put the dry signal down so all you hear is the essence of it in the background ) , and maybe add something like a piano that comes in when the plucks fade or a new synth..
I know this is a work in progress so you still have a lot to do but yeah amazing work so far
Also another thing you could do ( i would do this ), is find a few other progressive songs and use them as reference. Not only for seeing how their sounds sit in the frequancy spectrum and studying that kinda stuff, but also to study how they structure the song and keep it interesting. Im sure youve heard it but have a listen to
