You can create specific topic for every problem you encounter and the Community can try to walk you though the solutions. It should not be necessary to speak personally to achieve what you want.
There is something wrong here. You should be able to use standard Windows tools for writing .iso files to create a bootable USB stick. You should probably create a separate topic for that and the Community can try to help you resolve the issue (and you can create the video after that).
By the way, installation of Qubes from Windows indeed needs a better support, see this: Improve secure installation media preparation process for Windows and Mac users · Issue #6191 · QubesOS/qubes-issues · GitHub.
Where exactly do you get this error? During writing the .iso? Which tool for creating the USB stick did you use? Did you verify the signatures? During the installation? At which stage? As I said above, you should create a separate topic for that and answer there, in order to not clutter this one. Same for your other issues.
It’s not Debian installer but Fedora installer, because dom0 runs Fedora 32.