i just came from a qnap qts system. they had a qwa wireless addon card i was using before which worked with their native app ap station. this let me setup a wifi ap on the nas. this way i could have a faster wifi connection, because my other ap is located elsewhere and so has a worse signal. thats my case use and why i myself might want to somehow get this to work but with truenas.
but considering the difficulty to do this, might just be better off getting a mesh ap and put them in different areas (wired backhaul ideally. if not possible then wireless backhaul) e.g. deco mesh or something else wifi 6e or 7, then call it a day.
so like others mentioned TS, maybe have rethink about this 
cauz i certainly did.