The loss is only one facet of the problem - the round trip time becomes a significant problem, requiring large windows and timeouts and general weirdness - time travelling ARPs, for one - as does the ability of consumer equipment to send a signal your AP can receive. The Wi-Fi antenna in a phone or laptop is not generally very powerful.
The limiting factor isn’t the AP, in short.
Now, running LTE microcells - that’s a viable option in a desperate environment, and one that can be done with SDR. Only problem is then getting consumer equipment to authenticate with it. This is possible, either with eSims or with cooperation from local regulatory authorities - but not altogether trivial.
This is borne off the back of experience - I tried to do long range Wi-Fi, but for a usable experience from consumer gear (a phone), 2.5km was about as far as I could get with a 1 watt amp on a dipole.
Got much further with a yagi, but funkiness emerges beyond about 4km on 802.12g. You’d get further on b but your rates will be pants.
I would do LTE for this application. My solution where I am is a mast that receives LTE atop a hill and has four yagis doing 802.11g to receiver nodes, which each comprise a repeater with a yagi pointed at the mast, and a dipole omni to get a solid 500m radius around each repeater. I’ve covered 15ha of tortured terrain with Wi-Fi with this - and come to think of it, the highly directional signals could provide hardness against interference and would greatly mitigate interception issues.
Oh, and I’d you’re doing yagis, you need real ones, not the fake crap you’ll usually find for sale. The real deal is about 70cm long for 2.4ghz and will have tapered vanes to the point. Commercial models come in a plastic can.