Hi Jake,
Wish you luck in getting the QDX.
I have run WSJT-X on my Raspberry Pi 4, and it is slower than my I5 laptop.? If possible I would suggest the Raspberry Pi 4.
I have not tried the Pi Zero 2, but based on my Raspberry Pi 3 experience, I do not think it will have enough capability for FT8.? Since RTTY is not doing the deep decoding that is in the FT modes, I believe that any of the Raspberry Pi versions can do that.
73
Evan
AC9TU