Bluetooth audio devices stop working after a few minutes Update Dec 3: I keep experiencing this issue whenever there's little memory left. I.e., Bluetooth audio stops behaving correctly whenever Memory Pressure in Activity Monitor is high; the only way to get it working again afterwards is to disable and re-enable Bluetooth.

When I connect an audio device and use it to play music, audio stops working after a few minutes and switches to internal speakers instead (but the device continues to be shown as "Connected" in Bluetooth). This happens with all my Bluetooth audio devices (3 in total). I don't experience any of these issues when using the same devices with my smartphone. The issue started around a month ago, roughly at the time when I upgraded to macOS Catalina. I'm using a MacBook Pro (Retina, 13-inch, Early 2015).

I have tried the following steps already:


Moving my bluetooth device right next to my laptop
Updating to macOS Catalina 10.15.1
Disabling and enabling Bluetooth
Restarting the laptop
Removing and re-adding all Bluetooth devices
Deleting the file "com.apple.Bluetooth.plist" in /Library/Preferences/
Resetting PRAM
Searching StackExchange and the internet for more advice


None of these have helped, not even temporarily.

This is what it looks like when the issue is present:



When hovering over the audio device, its name disappears; when clicking it, the audio menu bar icon becomes animated and looks like it's searching/loading in a way I haven't seen before.

At the same time, the device looks normal in Bluetooth:





I'd greatly appreciate any help!
I tried a whole bunch of additional things that are related to sound rather than bluetooth. The issue is now resolved. I don't know which of the steps fixed it but if you have the same issue, doing all of them will likely resolve it:

1. Reload coreaudiod

Enter the following into Terminal:

sudo killall coreaudiod
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.audio.coreaudiod.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.audio.coreaudiod.plist


Then restart the laptop (or do step 3 (below) at the same time).

I got errors when doing the above, but perhaps it still helped somehow.

2. Unload the kernel extension

sudo kextunload /System/Library/Extensions/AppleHDA.kext 
sudo kextload /System/Library/Extensions/AppleHDA.kext


Again, I got errors when doing the above, but perhaps it still helped somehow.

3. Reset the SMC

Shut down the laptop, connect it to power, hold the four buttons cmd-option-shift-power for at least 10 seconds, release, start the laptop again.

--

After performing these steps, everything was back to normal.