Innuos as Core and Streamer for digital solution w Roon

Yes, it will work very nicely as a Roon core provided you dont do a lot of DSP in Roon.
I owned the Zenith MK3 and loved it. 
While it did Roon quite well but IMO their own Sense software is even better sonically. 
you get the best of both worlds really. 

Also, I tried the Zen Mini and didn’t find it to much better than the Node. 
I would at least try their Zen MK3 if not Zenith. The SQ difference is quite substantial between Zen Mini and Zen. 

I tried Aurender, but ended up going with the Innuos.

Zen Mini MK3, and Zen 3 are in my systems. Both work perfectly with Roon.

Like most things digital, going up the ladder means improved resolution. But, if you are constrained by finances, the Zen Mini is very capable. You can forgo the external power supply by using a really good power cable like the Audioquest Thunder/Tornado/Hurricane(though it probably costs as much). And using resolving USB cables like the AQ Diamond also upgrade the sound.

I really hate pushing more and more expensive items, but, from my old ears, you really do enhance the sound quality when you add these 'tweaks'.

Bob

Bob, do you think there’s a noticeable improvement from Mini to Zen M3