I may be missing something but I have flag return/pick up problems. Sometimes the moment our FC dies the flag gets instant returned so fast it's not funny. Is there a special keybind I'm missing?
Even if you do keybind the scroll wheel you will still be doing as good as someone who clicks but has 100ms lower then you. I'd just what sally said and click faster
If you can bind it using the touchpad, you can do it using the touchpad.
However, if that is the limit of your hardware, I would not recommend unbinding zoom to do it... 2 finger gestures are complicated enough without throwing in modifier keys, and just clicking the flag when using a touchpad will be significantly more reliable than binding flag returns to a gesture, if not quite as fast.