Access Diagnostic Screen Programmatically

How do I access the diag screen programmatically on a Honda Clarity 2018 PHEV non-touring (with root)? Clarity's has a damaged HMU (touch digitizer not functioning). I have root on the unit, and USB/wireless debugging is enabled, so I am still able to operate the head unit (through ADB shell, or somewhat through the frontend by sending emulated input keyevent or other key events). However, this leaves the touch keys on the side of the screen inoperable, as they are not (to my inference, thus far) considered virtual navigation keys, but rather appear to be additional hardware input device keys. I've checked the listed key codes within system/usr/keychars and system/usr/keymaps, but sending these through ADB doesn't appear to do anything. Furthermore, even if I am able to find the correct input keyevent codes, I'm not certain it will be possible to invoke the Audio+Menu+Brightness keys together, and whether doing so would work to invoke the diag menu? I've also thought to directly call systemdiag through adb shell start, but none of the activity URI's enumerated via systemdump appear to be accepted, and all result in component name errors. I'm sure this should also be possible, but I'm not sure whether I'm committing a syntactical error or just using the incorrect activities altogether.