If I understand correctly it sounds like you are not using GlassWire 1.0 from Steam itself, but instead you’re using GlassWire 2.0 from our website. And the 2.0 version of GlassWire from our website does not let Steam work for some reason.
If you install this beta of GlassWire 2 after uninstalling your current GlassWire 2 version, then rebooting, Try the GlassWire Windows 2.0.81 beta! then choose “clean uninstall” and “reset your firewall settings” while installing does it fix it?