Best Connection Between MAC and NAD

I have a MacBook Pro and just received a NAD C 399 with MDC2 BluOS-D module.  I'm trying to figure out what is the best way to connect them.  I started using Apple Music and coming out of the MAC headset jack into NAD audio inputs.  The quality of that audio was OK, but not great.  I attempted to use an USB-C - HDMI adapter cable into the NAD, but that did not work.

Then, I signed up for Tidal and connected a USB-C out from the MAC to a USB input for the NAD.  I believe this enabled the use of the NAD DAC.  Those helped the sound quality.  But, now I'm wondering if I should explore an optical option.  Coming out of the MAC USB-C and either using an adapter cable or dock to come out an optical connection and into the NAD optical port.

Any suggestion what would be the best configuration for connecting the MAC to the NAD?

Thanks!