Comment 3 for bug 1851265

I'm seeing something very similar. Judging by dmesg output, file descriptors from bluetooth connections aren't cleaned up after suspending, which blocks new connections back to the device. It usually fixes itself when the OS is shutdown(not rebooted), or operates without suspending for a few hours. Dmesg:
[159056.186990] usb 1-4: new full-speed USB device number 14 using xhci_hcd
[159056.187129] usb 1-4: Device not responding to setup address.
[159056.187189] debugfs: Directory '21' with parent 'devices' already present!
[159056.395246] usb 1-4: Device not responding to setup address.
[159056.395296] debugfs: Directory '22' with parent 'devices' already present!
[159056.603067] usb 1-4: device not accepting address 14, error -71
[159056.603164] usb usb1-port4: unable to enumerate USB device

Bluetooth was a lot less flaky in Kubuntu 19.04 then it is in Kubuntu 19.10