There are some no name USB capture sticks that take any HDMI signal and expose it as a standard USB UVC camera, no drivers required. This could be a start of a DIY project.
Funny that the reverse has already happened due to Apple's lackluster support of PWAs. PWAs run with the system's browser engine, unlike Electron apps that ship with their own customized Chromium engine. Each app is only a few megabytes tops, unlike the hundreds of megabytes of bloat native apps tend to take up nowadays.
Indeed, many of Ventoy's magic come from GRUB2, Ventoy just wins in ease of use by autodetecting whatever's tossed onto the drive without manually editing the boot menu.
Personally I would follow Microsoft's guide on partitioning [1] mostly, except the recovery partition which I skip creating. If Windows needs it they will auto create it again anyways in the next major update.
Then I use WinNTSetup [2], just point it to where the Windows setup files are, and which partition is the boot partition (EFI partition) and which partition is to become C:.
Microsoft actually has a guide for manual partitioning, which this guide does not follow. [1] The Microsoft guide cleans the whole disk and ensures the 100MB EFI partition is before the 16MB MSR partition.