warning, old thread banter
purely anecdotal advice; years ago i explored a similar need as i live across from a city park (i did not go thru with it because this park was surrounded by 7' metal fencing which acted like a Faraday cage, so the only way i could get any signal was sitting on a specific bench while the park gate was left open). i would consider getting an access point device (plenty of used 2 long stick AC models on ebay) you can mount outdoors (or indoor window glass) that extends the lan dhcp your ax88u is already hosting. going that distance may require you use 2.4 on the client, so it would be fine to use 5.0 as the backbone between routers, or wired if you can manage it. if you are concerned about nosey neighbors you can hide such a device in a window AC bracket or a window track you then spray paint the device the same color as your window frame. i did this with a bullet security camera watching for ground movement under my 2nd story window and nobody seemed to notice or care (fortunately in the years since all i managed to cam catch was the gardener mowing the grass, and squirrels fighting).