Unfortunately, the simple answer is that you can’t do either or these things. As far as As far as I know, none of the lower cost digital desks have crossover functions yet, though I’m sure that is a feature that will be included in the future.
It is tending to become a built in feature in some amps these days, and does not seem to add an enormous amount to their cost.
As I assume you will already have amps though, I would look for a simple crossover or speaker management unit that performs both these tasks, and mount it with the amps. That means you can use your speaker system with other sources, not just your QU, which is bound to be useful at times.
