Set Kdenlive to DirectX11

Summary

Kdenlive is set to DirectX9. Shotcut is set to DirectX11. I assume it would be better to make sure Kdenlive run with DirectX11 as well.
Does this has something to do with the video scopes not working under DirectX?.

ADDITIONAL INFORMATION

@mardelle: Shotcut on Windows seems to use an old Qt version (5.9.7 in the build script) while we use much more recent versions (5.14.x or 5.15.x). DirectX11 apparently is problematic with some drivers/cards (https://doc.qt.io/qt-5/windows-requirements.html ) so enforcing it is maybe not a good idea.
@emohr: Do you mean about min. version of OpenGL 2.1 needed? This should be no problem as 2.1 was introduced 2006. I have OpenGL 4.6 (on Win7&10).

@mardelle: I could send you a patch for Kdenlive enforcing DirectX 11 through the environment variable method if you want to try it and make some tests...
@emohr: Yes, it would be interesting to test Kdenlive with DirectX11. Let me know how to do that.