Simple English is what you seem incapable of grasping. "Cards from mid-2015" is very clearly referring to... cards from mid-2015. As in cards that were released in mid-2015. I can't imagine the mental gymnastics it would take to read that as meaning cards released after that point.
That's completely meaningless. They work on an early, leaked version of Windows 11 that's essentially just Windows 10. That implies absolutely nothing about support for the final version. Most of the underlying OS hasn't even been updated to call it Windows 11 yet. There are still references to Windows 10 everywhere under the hood, which is what driver installers and such will be seeing, rather than the new logo hastily slapped on the UI. Every version of Windows is essentially just a redesign of the previous version with some under the hood changes, yet driver support doesn't carry forwards. Hell, driver support sometimes hasn't even carried forward between different versions of Windows 10. A sound card that I have works on older versions of Windows 10, but not the latest couple as Creative dropped support for it in the interim, and the drivers for old versions of Windows 10 don't work on the latest version.