Initial fixes made to the swapchain handling to enable applications to start on Windows 7 with the D3D11 backend, but reported to unable to render content. Did not have a Win7 setup myself to test this.
There were some uncertainty in R&D circles about dropping Windows 7 in Qt 6. Confirm what the plan is. If Win 7 is still supported, things have to be tested and fixed properly.
As a sidenote, if Win 7 is a thing, verify that requiring Direct3D 11.1 (not 11.0) is acceptable. Any updated Win 7 system since ca. 2013 should have 11.1.