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. 

I will second the Wyred 4 Sound Remedy reclocker. It improves about any digital source even my CD player sounds better through it. Computers are very electrically noisy and are not the best source for audio but the Remedy really improves their sound. Also Wyred’s bLink is a good choice. Thats the version I have. Its a Remedy with blue tooth and works the same magic on blue tooth as well as allowing connection to another digital source. I would go so far as to say that with the bLink and a phone or tablet with blue tooth aptex capability streaming Tidal etc. that many would be happy with just that. It really is that good!

As far as which connection is best you just have to try and see which sounds best. If your computer has both options.

I stream Tidal via Roon from an Antipodes server/streamer to a Denafrips Pontus DAC using a Curious Cable USB cable and find it very satisfying. Not thin at all.

I would normally try a coax or optical connection but enjoy the way it is too much to change it around. Probably should for my own education...........or confusion lol.

You’re SQ is limited by using toslink or usb to the dac. Did that for over a dozen years and bought into the Usb tweaks, still compromised. Use i2s or Ethernet into a dac/network interface and get rid of all your usb and toslink stuff. 

@rbstehno I have a MacBook Pro 2013 and a PS Audio Direct stream DAC. The DAC accepts i2s. My question is how do I physically connect from the laptop to the DAC?  I don’t have an i2s port on my laptop. 

I'd look at Wireworld's range of cables.

Thanks for the input, while ive thought about going all digital for storage I have never followed through.

But having a dedicated desk top or rack mounted computer with a reclocked sound card "putting out a clean digital signal"  SEEMS the way to go.  my 390s will take 24 bit 192 khz. 

The rack mount computer can give you a large storage capacity etc. 

anything else ?  I found this today?  any thoughts on it? 

https://www.superlogics.com/industrial-computers/rack-mount-computers/long-life-rackmount/sl-3u-llq370m-ka.html?selectedOptions=eyJidW5kbGVfb3B0aW9uIjpbeyJvcHRpb25JZCI6IjE3OTU2Iiwic2VsZWN0aW9uSWQiOiIxNDM1OSIsInF0eSI6MX0seyJvcHRpb25JZCI6IjE3OTU3Iiwic2VsZWN0aW9uSWQiOiIxMTk4NiIsInF0eSI6MX0seyJvcHRpb25JZCI6IjE3OTYwIiwic2VsZWN0aW9uSWQiOiI2MjczIiwicXR5IjoxfSx7Im9wdGlvbklkIjoiMTc5NjciLCJzZWxlY3Rpb25JZCI6IjQ4NDUiLCJxdHkiOjF9LHsib3B0aW9uSWQiOiIxNzk2OCIsInNlbGVjdGlvbklkIjoiMzU4MiIsInF0eSI6MX1dfQ==

For my home Mac I use a Halide Design S/PDIF Bridge USB-S/PDIF converter.
At work I use a M2TECH hiFace Two with a coaxial cable.

Happy with both.

you asked that question,   I'm surprised all the answers didn't drive you nuts 

Black Cat Silverstar 75 SPDIF digital cable is well thought of.