This is what changing to the newest available HDMI board for the UHD722 will offer. Still no HDMI 2.1.

Functional changes:
New board: HSR-82T
Inputs 1-7 HDCP 2.3
Inputs 1, 2, 3, 4 & 6 HDMI 2.0b
Input 5 & 7 HDMI 1.4b
Output 1 4K 4K
HDCP 2.3
HDMI 2.0b
CEC CEC
ARC ARC
Dolby Vision
HDR10+
Output 2 1080p 4k
HDCP 2.3
HDMI 2.0b
HDR10+

Note:
When displays are connected to both outputs simultaneously, certain features must be supported by both
displays in order for the source product to be told that those features are supported.
This means that, if one or other of the displays does not support the feature, neither display can take advantage of it.
This applies to 3D, 4K, HDRS, COLOR and HDR10+.