SBC XQ provides a better sound quality than APTX-HQ. It's considered transparent : 100% CD quality.
A good article about Bluetooth codecs on soundexpert.org
SBC XQ is available from scratch in Zenwalk ;)
Enjoy the best BT "lossless" quality available on GNU Linux !
Here is the patch, for those who want to use it to oher distributions : https://gitlab.freedesktop.org/Hyperion/pulseaudio/tree/SBC-XQ