[Cycle though my brushes in brushes palette]

My digital art creation depends on being able to quickly cycle through the brushes palette, from one to the next and back or to the next, with keystrokes. Having to turn away from the work and gaze to the pallet to physically click on the next brush disrupts my work flow.

[Ability to create G-code for CNC manufacturing / laser cutting]

Anyone know how to fill a stroke on Affinity Designer 2 (as in Illustrator) so that a CNC can follow it for cutting out of steel?

[How do I cycle between brushes?]

I've been an Adobe user for decades and am now sans Adobe and learning both Affinity Photo and Designer. I have 120 personal brushes that I create with and would like to cycle between them while working. Is there a key combination with which to move backwards and forwards in the brushes panel?