You may have resolved this problem already. I see you've been asking around. But, in case it's not fixed:
Do you have another non-Win10 computer you can install it on? (Maybe your kid's computer
) I haven't actually installed Il2 1946 for many years, I just keep copying my old installs. If you can install it somewhere and copy it to a thumb drive, you can copy the IL2 folder to your Win10 system and it should work. I'm using it on Win10 with minimal problems, you have to use your desktop at 100% scaling or your mouse won't work. I change from 125% to 100% when I use IL2, a minor annoyance.
Cloyd