Oh, I missed this! I know the answer to this one!
No. There is no NetMD software for Mac.
In 2005, Sony released
HiMD software for the RH/DH710. RH910/10, and 1 for the Mac, but it only works with LPCM recordings and MP3s on those devices. (*Should work on previous HiMD recorders but only with the LPCM audio, earlier generation HiMD machines can't run MP3s.) The HiMD transfer also won't work on classic mode discs.
Unfortunately, overall, Sony hated Macs and/or was simply too lazy to do any of the work to get this working on Macs, so your best bet if you absolutely must use MD on a Mac is to use a USB TOSLINK sound card (such as the MD-PORT DG2) and record live. (What machine do you have? That should work on anything minus an NE410/D420N/DN430/NF520D/NE810)
There were some early attempts at third party MD software back in the MD era but none ever got so far as to be able to actually load audio onto the discs.
If you have a modern computer, the best modern tooling is Web Minidisc:
https://www.minidisc.wiki/guides/webminidisc