Phone : OnePlus One I have recetly installed Anbox on my phone while waiting for Waydroid to mature more. Hopefully its easy to switch over when it comes times. In doing so, one thing i have noticed is what OP os talking about. Usually what i have to do is run adb kill-server Reboot the phone and then try adb devices and that should show your device with it being online

@luksus I actually bought a Pinephone, but the OnePlus 3 is so much faster and also has more memory. The only thing the pinephone has over it is the hardware kill switches. I will try and install anbox and see if if performs. Thanks!