I’d be wondering what’s wrong with my Roon. I would expect minimal differences, if at all, although Chromecast has some issues at least with hires. Or you like the effect that it has, or there are other factors, like your head 
Did you correct for loudness differences? (Is volume leveling or any other DSP enabled in Roon?)
When using Chromecast the stream is bit perfect and native upto 192kHz/24bit. The downside of Chromecast + Qobuz is that it’s not really designed to run at such high sample rates. The buffer sizes are far too small (hence prone to drop outs) and the Chromecast stack is very inefficient so uses nearly all the CPU time in the streamer. Not only is this bad for unit response times, but not also great for sound quality as the electric noise floor of the product increases as everything works harder.
From NDX2 Qobuz via Naim app or Qobuz app + Chromecast? - #18 by Stevesky