|Using different bands may help.|
Using one of those power line connectors may work.
Pretty easy and safe to run a fiberoptic cable. Just call before you dig.
Some brands offer external antenna so each end could have an exterior cable.
All the wireless stuff may also be bad as a result of many other factors. Competing signals from all sorts of products and sources can wreck your signal.
By the way. A special tin coated building is generally the place to escape signals to testing and controlled calibration of equipment.
A Pit Bull is like a gun you can pet. And there is no safety on it.