Whats the popular brand, most musical, digital cable now? What format?

Wait- you want what's "popular"? Or what's good?
I ask because you also say, "I hope its not thin sounding."
All the really popular stuff is thin sounding, although I prefer to call it hifi as that captures a lot of other faults at the same time and in only 4 letters.

The audio output port on a Macbook is a combination analog and digital output. You can plug a stereo-mini analog cable into it to get output for headphones or to go to the analog input of some other amplifier.

To use it as a digital output you would need an optical mini-Toslink to Toslink cable, either glass or plastic fiber, which will transmit the digital stream using the Spdif protocol to a digital/analog converter.

If you go that route, which I do, you can improve the sound quality quite a bit by using a reclocker between the Macbook's digital output and your DAC. Wyred4Sound makes a very good one, the Remedy Reclocker, and there are others. The reclocker isn't required but will help with the significant amount of jitter in the Macbook's digital output.

One more thing, Macbooks from 2016 and later don't have digital output at the headphone jack, the only digital output from them is via USB.