mjw
(You want nice, supportive? Call a damn helpline.)
2
The WiiM is a Roon Ready network streamer, so connect it to your network, not the Mac Mini. This device is one zone.
Any devices connected directly to the Mac Mini via USB are additional zones.
Each zone can have different DSP. Headphones may also have different EQ settings, but you will need to create these, save them, and select as needed, depending on your zone setup.
So, it may be beneficial to describe how you would like to use Roon and each of your preferred zones.