What should I use: from Mac Mini to Router. Network cable or WiFi?
Ethernet can be more trouble free than Wi-Fi.
If you maintain a good Wi-Fi network and are comfortable with tweaking it , it can also work fine, really depends on how busy your internal network is.
If the Mac Mini is your Core, i would have it cabled to the router, as is recommended.
Dear Pedro D, Thank you!
By network cable?
Yes by network cable.
I actually wanted to spark a debate about the two ways to plug into the router (cable or wi-fi). Which of the two has a better result?
This has been covered ad infinitum in this forum.
Official Roon recommendation is Ethernet cable wherever possible.