The filter was clean. There's still no explanation for the cylinder 3 misfire/hide cylinder, but considering the mileage and it being cylinders one and two with detonation furthest down the line on the rail, fuel injectors and carbon cleaning while they are in there makes sense to me as a next step. I have four of these injectors on the way
Bosch 06L906036AK. They are significantly cheaper than the GTI injectors, flow 15% more, and EQT can accommodate them in the tune. Will also probably go with a new, OEM HPFP.