Ayrmesh is nothing more than Ubiquiti hardware that has been flashed with a custom firmware and programmed for idiot-proof installation.  Their radios don't travel further or penetrate any metal buildings any better than any other properly configured radio.  Furthermore (and you know this) there are limits as to how powerful radios can be and still be in compliance with FCC regulations.

The Ayrmesh product you linked to is a Ubiquiti Bullet M2 radio.  It can be had for $79 and will come with the POE injector to power it.  The antenna they are using is an Omni-directional antenna. It does not appear to be a Ubiquiti branded antenna but I doubt it costs more than $50.  So $130 of product.  One of the worst things that a person can do when designing a wireless network is to use an omni-directional antenna.  It is subject significantly more interference than directional antennas.  On top of that, the Bullet M2 is historically one of the least reliable Ubiquiti radios as its design is subject to water leaks.

My recommendation.....stick with a point to point bridge and pay someone if necessary to set it up.