As far as I understand you need to download the app either from iOS or android unfortunately.
Yes, I'm almost happy and excited to try when look the application has Windows and Linux
download, but after installing, I still need login scan from the Android or IOS application, and I can't find also a button which I can log in use phone number on windows application, this mean installed application in a phone is necessary.
1 more important thing is I can find mixin applications on play store when my phone didn't connect VPN. this mean the aplication is not available in my country Indonesia.
therefore I can't join your service.