(I have the over the ear XM3 that don't support multiple devices, but also have a Bose 700 that does. The Bose 700 does AAC, but I find SBC-XQ better. On the Sony it's a toss-up, so I stick to LDAC. I'm using Fedora Silverblue 39 with PipeWire for reference.)
That scenario would definitely be the time to use SBC-XQ.
http://soundexpert.org/articles/-/blogs/audio-quality-of-sbc-xq-bluetooth-audio-codec
(I have the over the ear XM3 that don't support multiple devices, but also have a Bose 700 that does. The Bose 700 does AAC, but I find SBC-XQ better. On the Sony it's a toss-up, so I stick to LDAC. I'm using Fedora Silverblue 39 with PipeWire for reference.)