Are there anything in journalctl output (executed as root) around these
events?
I guess that no, but i will recheck.
Is XFCE configured to use pulseaudio or PipeWire as GNOME?
Pulseaudio
Another option might be LC3 codec from Bluetooth LE (5.2 Basic Audio
Profile) if it is supported by the headphones.
Unfortunately it's not supported.
Either a software/hardware bug or some piece of software disables power
saving for handsfree/headset profiles to achieve low latency, but for
A2DP device tries to sleep after some period of time.
Hm, i will try to research that, thank you.
Arch Linux wiki pages have long troubleshooting sections.
Yes, I saw but found nothing relatable to my view.
Last resort might be dumping bluetooth traffic, but perhaps it is better
to ask in some mailing list or forum more close to Bluetooth stack
developers.