JNUSTool VS steam-gyro-for-cemuhook

https://github.com/Maschell/JNUSTool is what I recommend.

Download the latest JNUSTool

JNUSTool

i use this app for https://github.com/FrogTheFrog/steam-gyro-for-cemuhook i play Zelda the breath of wild and works very fine

Since you just got the controller I would recommend using the default controller config on your steam controller settings. Launching a game on yuzu and then going into your yuzu settings and select "Pro Controller" and then for Input Device select Xbox One Controller. Now dont mess with the steam gyro settings use this for gyro I have heard that this program works : https://github.com/FrogTheFrog/steam-gyro-for-cemuhook

{LINKS} https://github.com/FrogTheFrog/steam-gyro-for-cemuhook

There's an archived project for the Steam Controller, but it unfortunately doesn't detect anything from the Steam Deck: https://github.com/FrogTheFrog/steam-gyro-for-cemuhook

Already have Steam Gyro running but: I tried using XInput and the setting stays disabled/grey (altough that was expected). Tried using DSU and it can be enabled but the pad doesn't really work as I configured it through Steam (to not require click to work and such). Tried SDL but the setting stays disabled/grey.

I don't know about event logging. There's also steam-gyro-for-cemuhook, sc-controller and I believe VSCView which can all directly communicates with the Steam Controller. Perhaps one of those can log the inputs received.

To verify whether it is the controller at fault have you tried testing it with the BPM controller settings test screen? Alternatively you could use somthing like steam-gyro-for-cemuhook which also can display what the SC is reporting.

The steam-gyro-for-cemuhook program can show you what the gyro is reporting. That way you'll know if the hardware is working.