Swapped an AVR, can't get audio/video from the matrix

[pshrop]

I swapped out a Pioneer AVR that was ~10 years old and repeatedly losing it's network connection for a new Onkyo TX-NR5100 (please don't judge my frugality, it's for a 3.1 setup in a kids playroom that gets very little use beyond a PS5). After hooking it up and working with someone to remotely swap the devices/drivers in my project, I've got everything working the way it should except for my LU1082D matrix feed. I ran the calibration, but still can't get audio out of the speakers or video on the TV when the source is my LU1082D matrix.

Troubleshooting:

• There are no other issues in any of my rooms
• I've swapped out lots of cables, am confident that's not the issue (and all these cables worked with my previous AVR)
• The video feed comes thru to the TV if I bypass the AVR and go from the LU1E directly into the TV
• The PS5 and other inputs into the AVR work across all the HDMI inputs, but the matrix feed won't work in any of the HDMI inputs
• The only AVR setting I could find that I thought might affect this is the 4K Standard / 4K Enhanced / 8K Enhanced toggle for the HDMI inputs, but none of these made a difference
• CEC on the AVR is off
• If I plug my old AVR back in, the audio/video feeds passes thru the AVR without issue

Could there be another setting within the Onkyo controls that's messing this up? I'm nearing a point where I take it back and try a different one.

Thanks