I’ve seen “No desktop or application available” if Citrix isn’t installed or not fully installed. Once on 9.1.6108 then try to push the new Citrix 21.12.._3. You can always install the firmware and leverage the existing Citrix push the new Citrix afterwards.
Also try deleting Citrix from the packages and reboot and have it install again. I’ve seen sometimes where the Citrix Workspace package is installed but it’s only 100MB or 200MB not the normal 600’ish MB so somewhere it got corrupt during install. Deleting and rebooting using fixes it provided the package is in your policy to install on check-in if missing.