Here are some updates right from a Yamaha insider.
The current AxA line have a serious YPAO bug that will not allow accurate calibrations if more than 3 measurement points are used (will results in speaker distance error that will cause serious comb filtering effect). Atmos + DD+ will results in erroneous object location when AI is used. And finally, the low SINAD on the Center, and surround channels is hardware related so it cannot be fixed by future FW updates. Yamaha engineers are aware of this and promise to replace some component in upcoming future revisions of these AVRs (mid 2022).
So the bottom line, you should avoid the new line of Yamaha AVRs until after the second half of 2022 (component shortages is the blame for the long delay).
here is another source that confirmed all of the above (use Google translate):
YAMAHA - A8A התרשמות ראשונה . | אודיו בקולנוע-ביתי ופורמטים רב-ערוציים - רסיברים, מגברי כח-רב ערוציים, פרוססורי-אודיו וכו'
htmag.co.il
I personally spoke with the manager of the official local Yamaha dealer, and he has also confirmed all of the above.
So A6A, if finally off my list for good. I'll wait for either Onkyo RZ70 (coming in April 2022) or Denon X6800H (mid 2022).