Not sure if this will help anyone but I have dealt with HDMI handshake issues with my JVC projector in the past when using 4K products and it has been been talked about in avsforum.com threads for awhile.

The most helpful tip besides having high speed cables deal with cable length. Obviously long cable runs (more than 8-9 m) are a problem but so is a short cable.

Using anything less than 2 m length gives handshake issues (at least with the JVC projector).

This may have already been stated and I don’t have the UHD722 to try it out.
Maybe someone can test this out in practice to see if it makes a difference.

My gear: Trinnov CI, 271, 8000.1(SEs), 7200.1 HC (SE), 320s, 3200s, Seaton F18 subs, MS200 (2nd zone), 218, 210.
Other: JVC RS-4100 projector, Lumagen Pro Radiance, Panamorph DCR anamorphic lens, Stewart G4 130 screen, Kaleidescape Strato K, Rvolution 4K player and Zapitti NAS, Oppo BDP-203,Roon Nucleus