The first paragraph:

It’s not complete HDMI 2.1 support but to much surprise hitting the mailing list today were official patches from AMD for implementing HDMI Fixed Rate Link “FRL” support for their kernel graphics driver. HDMI FRL as part of HDMI 2.1+ allows for higher bandwidth to support higher refresh rates and resolutions.

How much more of an explanation do you need?

It might have been nice to have Mint 23 out closer to the totally-for-real-this-time end of Windows 10 updates in October, but it takes as long as it takes, I suppose.

The articles says Mint 23 will include “Cinnamon 6.7-unstable”, and I hope that’s just what it currently is, and not that it’s expected to still be unstable in December.