Yes, the Kobo Desktop help page still exists:
https://help.kobo.com/hc/en-us/artic...your-PC-or-Mac
but as you noted, kobosetup.com just redirects to the web reader page. Since Kobo didn't bother to update Kobo Desktop for the Clara BW or Clara/Libra Colour, I suppose the writing was on the wall. You may be able to download the installer from a third party, but who knows how long it will continue to work.