Are you testing these speeds over wifi or over wireless? Wifi clients that will hit close to gigabit speeds are fewer than most people realize. Test it over ethernet to ensure you are getting your full speed at the tap.

Almost any modern access point system (such as asus’s xt series) can be very reliable solid systems, just have to be wired backhaul. Once you dive into wireless backhaul using A N Y of these companies built in wireless backhaul, you will start to have little gremlins. They work fantastic for what they are, but if you’re in the home networking sub reddit, you are going to get basically the standard of response of “use wifi for things that there is no other option”.

CPE710 wireless bridge to connect the two buildings. Then configure the xt9 for wired backhaul using the ethernet cords coming from the CPE710s. You’ll get 700+ mbit assuming you have everything else correct