We still wait for m.2 slot from RouterBoard platform.
For now are some adapters who works with RM502Q module but I use only cheap usb2.0 versions who will limit you.
Pigtails from mhf4 to sma etc. are very common to buy, select proper antenna are always not easy task.
Bonus
m.2 keys.png
You do not have the required permissions to view the files attached to this post.