I found the problem, and just want to document that here. Yesterday, I looked through every single setting in the app. The QoS (Quality of Service) setting was turned ON, and the bandwidth limits...

I have a mesh with three Deco X90s (one of which is my main) and four Deco M5s. Maybe a bit overkill, but this setup has worked fine for several years. A couple of days ago, I upgraded firmware on...