I also had a similar issue. Check if the Device Manager is constantly "refreshing". If so, identify and remove the device causing the malfunction. By the way, in my case, the reason for the refreshing issue was that there were several TV options under "Bluetooth Devices" (they came from video playback apps with screen casting feature installed on Sony TVs running Android system). Deleting all of them from your Bluetooth devices resolved the problem.

Moreover, here are some tips based on my past testing experiences:
https://forum.square-enix.com/ffxiv/...ntinuous-cycle

However, this post has already been closed by the staff of the SE forum. I'm not sure if you can still see it.