Here is what Sony support says:
Bran (11/20/2019, 7:23:11 PM): Yes, I understand you would like to confirm which is the HDMI 2.0 full bandwidth port. Am I correct?
Me (11/20/2019, 7:23:36 PM): Correct, different sources state different things.
Bran (11/20/2019, 7:24:46 PM): I would like to confirm if you are referring to HDCP 2.2 version.
Me (11/20/2019, 7:28:23 PM): Well if I have a 4k source what would be the best port?
I was under the impression that all carried the same bandwidth
Bran (11/20/2019, 7:29:39 PM): That helps, HDMI 2/3 ports are for 4K content.
Me (11/20/2019, 7:31:10 PM): ok, so use ports 2 or 3 ?
Bran (11/20/2019, 7:31:21 PM): Yes, absolutely.
I wish I would have know this years ago before I calibrated HDMI port #1
and suffered with intermittent handshake issues.