You can exclude your sidechain channel from the main compressor by routing it to Out EF instead of Mix AB.
If you want to record it, you’ll need to change it to Out CD and record both outputs over USB – I did think this was only useful for headphones, but actually Out CD goes over USB 3/4! For a live setup you’d need to either combine both channels on a mixer, or use the headphone socket with an adapter.
This hack definitely highlights how important this feature is, I don’t like the kick being compressed when sidechaining the rest. Hopefully they add an official way to do it over a single output soon (just being able to route to Out AB bypassing the Mix bit even would do) but this will do for now.