gulfgraph Sandman96 kyoichisudo
As evidenced by the experience of the original poster, unfortunately this symptom pattern is consistent with hardware failure.
One thing to try, though it would be disruptive, would be resetting everything related to Bluetooth (Settings, System, Reset options, Reset Bluetooth & Wi-Fi).
Arguably the next thing to try, though it would be much more disruptive, would be to back up all data and "factory reset" the device.
Probably the "big hammer" would be to flash the device back to Google's stock OS and use it for a few days.
If the Bluetooth hardware on a device is having trouble, then the trouble will remain even after all of those steps are taken. It's probably a good idea to keep a careful log for a week or so of how often the outage events happen, to be able to judge whether or not one of the debugging steps has fixed the problem.