I was hoping that MacOS was different than Windows but I guess not.
Microsoft discontinued support for Internet Explorer and the Java script that was used by GWS to generate the distributor certificate used a library that used Internet Explorer, looks like even on the Mac.
Good news is you downloaded Tizen Studio and you can generate the Distributor Certificate with that.
The bad news is when I did with Windows GWS had a bad password or something error. I don’t know if it will be the same with Mac version of GWS but give it a try.
Having SDB and Certificates created you can side load (run on device) using an old Gear Fit2 installer.
Here’s the link to the full instructions on Fit2Installer on the XDA forum with download links for the Fit2Installer app: [HOWTO] Sign and sideload Tizen applications to the Gear Fit2 (from Windows) | XDA Forums
Please let me know how it works especially if it works with GWS on a Mac.
Ron
Samsung Developer Relations