I just rooted an Onn UHD box from Walmart using Magisk and now I'm worried that I'll lose root during the next OTA update. Do I need to be worried, or will either A: root remain, or B: OTA updates will fail? The last update was in February so I'm nervous a new one will strike at any moment.
No, I think OTA updates will remove root altogether but I think OTA updates fail if you have a custom recovery. If your android box ever does update you should be able to root it again.
Sorry I don't know much about root on a android box as I do on a phone.