Some days you just have to pull a rabbit out of a hat.
Using a Metra 5x1 HDMI splitter to keep an old playroom TV usable, the Metra remote would not change inputs. The one Metra entry in the URC database did not work. So I started fumbling around, and discovered the Monoprice switcher worked on input 1 and 2 only, but other codes marked b-3 and c-4 did input up and down.
I still believe in miracles.
There is no truth anymore. Only assertions. The internet world has no interest in truth, only vindication for preconceived assumptions.