@relaxasaurus a few months in I knew what you described above was missing so I took the plunge and got a c10x to match the m10x. The change from the 900u to the 10x is substantial mainly on the mids and lows.
if I wasn’t someone chasing the best sound for the setup I have etc I would be more than happy with the 900u but as most of us on here, if we notice room for improvement we will chase it.

