The WH-1000XM3 are just about the only recommended bluetooth headphone anymore that makes switching devices that much of a pain. Most will either automatically switch between a few active devices or allow you to switch by just initiating the connection from the target device. Have you looked at installing the patched pulseaudio-bluetooth modules to gain LDAC support? :)
Have not looked at any fancy pulseaudio setups. I don’t want to maintain them on my machines over time, as I use these headphones with 4 different devices :)
Good news is that there's some more activity towards upstreaming them; at least in my experience, they Just Worked(TM) as far as the system automatically selecting LDAP or AAC as needed.