SMSL SU-9 vs Topping D90, What would I miss?

Planning to buy a DAC to pair thee Topping A90. I know D90 would be good but it’s a bit pricy for me atm. What’s the main difference between D90 and the SU-9? Would SU-9 + A90 a good combo?

Headphones: HarmonicDyne Zeus, DT880 600Ω, HD800S
IEMs: Fir Audio M5, Moondrop Solis, Empire Ears Odin
Sound preference: Neutral, large sound stage

Thx any advice!