under that little window of plastic is a switch to disable the 5v protection.
My own experience was that the PSU sends a bit more than 5v at boot up, but once load picked up it was fine measured at the jamma edge. On my new Astro I disabled the protection circuit after talking to the HW devs about it..
But then a couple weeks later I swapped out the SD card for an NVME install, which drew even more power.. so I now just power the pi from a wall plug so I didn’T have to worry about my PSU sending too much to the monitor etc.
I power on the pi, wait a couple seconds, then turn on the cabinet and all is great