As I mentioned earlier, I have managed to build KiCad 6 for Windows 7 for a while now and a couple users here have shown interest and have tested it. I personally use it on a daily basis.
So of course I did try building v7 for Windows 7. Required only a minor change compared to v6. So, I built it, but I have an issue. Everything runs except the schematic editor, due to a dependance on Win 8+ functions from the Windows API. From what I've checked, KiCad code base doesn't directly use any such functions except for CreateFile2(), which has a conditional compilation anyway, so it's not a problem. But the other dependencies are due to MSYS2 (which I've been using to build KiCad on Windows) not supporting Win 7 anymore now - so their libraries are not made to be compatible with Win 7 anymore. It's pretty recent (although MSYS2 have been warning us for a few months, but they made the switch like a week ago.)
Don't know yet if I'll be able to circumvent that without having to go through hoops. It's probably going to bite for building other software than KiCad on MSYS2 too.
That had to happen. :'(