First WISP setup, can I install Wi-Fi 6 in a RB4011iGS?

Greetings, I’m new to the forums as I’ve yet to really push my limitations with my mikrotik equipment.
I own a CRS317-1G-16S+ that distributes internet to my equipment via some generic quanta gigabit switches, and a RBwAPG-5HacT2HnD for my personal 2.4G WiFi.

I’d been hoping to cover an omnidirectional 600ft area or more in dual band 2.4/5GHz coverage WiFi with speeds of over 54Mbps back and forth.
I’m able to reach mixed results with a RBwAPG-5HacT2HnD and a 33ft tower, my phones receiving -80 to -90db around the 600ft mark depending on phone model.
A signal strength like that gets me around 5Mbit/s which is functional but not practical for any market competitiveness.

I was hoping to get both increased speeds and signal quality by investing in a RB4011iGS+5HacQ2HnD-IN as it not only has more antennas (4) but also better and external antennas that can be extended with a wire inbetween. I’m also highly requiring of the SFP+ capability as I’m otherwise hesitant to run cobber wiring from towers to my equipment lol.

The RB4011iGS+5HacQ2HnD-IN looks sufficient for my startup project however I’d been hoping to upgrade it’s miniPCI-E card to something more modern in the future. Is it compatible with this out of the box? Would I have to install openwrt on it and possibly lose it’s CAPSMAN capabilities? Anyone with hands on experience would be much appreciated to tell me about it.

Thanks for replies in advanced!

tl;dr:

  • can a RB4011iGS+5HacQ2HnD-IN with antennas at 33ft hit >54Mbps over 600ft outdoors?
  • can you upgrade the expansion card in a RB4011iGS+5HacQ2HnD-IN to Wi-Fi 6?
  • if no, what is an SFP+ compatible alternative?