I am not sure you would get any benefit from using both a Yagi and parabolic antenna and may even see a degradation of the signal. From my understanding the Yagi catches indirect signals by branching off the main antenna. While a parabolic antenna refracts the signal waves out in a conical pattern.
My bet is that the parabolic antenna would refract the signal back into the Yagi causing impedance. Essentially a large amount of interference or signal redundancy.
There is not harm in trying the combination as your
Mavic Air 2 has Return to Home (RTH). Or you can just take them off it does not work.
Your location sound about like mine. Open area then city. Urban areas are tough as the wifi saturation the main culprit of signal loss. I have been thinking about the Alientech Duo II. It is a powered 2.4 GHz and 5.8 GHz antenna and from what I have seen in both reviews and technical specs it should help. But it requires opening the controller and about $350.