This is what I've tried, but it doesn't seem to work.
Essentially in Bitwig, you have to hold down ctrl + option to then be able to use the mouse scroll to zoom in and out. Problem is that those keys aren't very convenient, so I was hoping to use the q key instead.
Any tips on potentially getting this to work?
The problem here is that any real hardware input interrupts any simulated hardware input. As soon as you move your physical mouse, the simulated modifiers are released.
You can probably use AppleScript to do this, but it's a bit janky and if, for any reason, something goes wrong, the modifiers can end up "stuck". As it's AppleScript, it's also a bit slow, so you would have to trigger it, then wait a moment before using the mouse.
I don't use Bitwig Studio, but am interested in it. On that basis, here are my thoughts...
You might want to try solving this problem with Steermouse or BetterTouchTool. See the discussion under Can the Mouse Scroll Wheel Be Used as a Trigger?.
I see that it is possible to zoom in and out in Bitwig using the + and - keys on a number pad. I can imagine that you might not find this an acceptable substitute for using the scroll wheel, but this way at least you wouldn't have to use the control and option keys.
Modifier keys are used frequently so should always be conveniently positioned. I wonder therefore whether they cause you problems in general. If so, consider relocating them (Karabiner-Elements or better still, use a programmable keyboard that uses QMK or similar).