Hello,
Here is some considerations:
1. MIMO is not working outdoor so you could expect 150Mbps rate maximum
2. Check "show wireless regulatory device-type ap7522
" for DFS and maximum allowed power
including antenna gain.
I could recommend two patch/narrow pattern antennas and 1xALL antenna mode. I.e. AP will use always one (primary) antenna to send signal and both antennas for listening. Use
this for link budget calculations.
Misha