Hello, everyone! I have had a Deco M5 system with 3 units set up in our house since August 2020. It vastly improved our in-house Wi-Fi coverage. However, I have an all-metal shop (sheeting on inside wals/ceiling AND outside siding/roof) that I am trying to get better Wi-Fi in that has a clear line of sight.  By placing a Deco unit in the back of the house near a window, I do have pretty good signal throughout the backyard now (sorry - no true numbers at the moment, just based on no issues with streaming music/videos), but the signal only goes into the shop through the small house-facing window a very small distance before speeds are unbearably slow. I have tried adding the 3rd Deco inside the shop in the window, but signal strength is only marginally better. It's manageable for my light-use of internet currently, but I am hoping to add some security cameras soon, and seems like Wi-Fi ones fit the bill in the shop. Of course, my home coverage suffers with the 2nd and 3rd deco placed in locations for the shop needs, so if this is the only good solution, another set of M5's may be in my future to improve the house again.

I would clearly like to avoid burying lines just from the work aspect, and have heard horror stories about buried Ethernet lines being hit by lightning and frying nearly everything downstream both ways. I know fiber optic line + converters is an option, but again, would rather do this another way.

So - is there any sort of outdoor antenna to mount on the outside of the shop facing the house, connected via wire through the wall to any-old-router on the inside of the faraday-cage-like shop?  Ideally, this would be a seamless system that would all be the same network much like the current Deco system is. Would love any advice or opinions before starting to throw money around like I'm in Congress. 

I appreciate your help and time, thank you!