Alright, further development: I have found the solution, but it is garbage in my opinion. Certain brush presets allow you access to these heretofore greyed out settings, and some do not. Why bother with this unnecessary lockout Affinity? Why not just allow that section of brush settings to be uncheck or checked as we please? This is a very unnecessary learning curve you've thrown into the software here.
For anyone who finds themselves stuck here to, switch to a brush such as one of the "Engraving" type of brush to allow these settings to be active, and be aware that they are not active for the "Pens" for some bizarre reason.