What the provider actually delivered
Your internet provider's job ends at the demarcation point — the box where their line enters your building. Everything past that is yours. That is not a complaint about them; it is the normal division of responsibility, and it is the same for every provider.
What it means in practice is that a gigabit connection and good coverage are two separate purchases, and you have only made one of them.
Why the signal stops
A router broadcasts in all directions and loses strength quickly with distance and obstruction. Across an open yard you might get a hundred feet of anything useful. Through a wall, less. Through steel cladding, effectively nothing.
Farm buildings are close to a worst case: metal roofs and walls, concrete, machinery, and distance. It is not that the connection is not fast enough — it is that it is not being carried anywhere.
The fix, in order of how often it is right
A point-to-point link, most of the time. Two radios with line of sight, and the barn gets the same connection as the house. It goes up in a day, needs no trenching, and can be moved later.
Buried cable, where there is no line of sight or the run is short and the ground is open. More disruptive and more expensive, entirely unaffected by weather or tree cover.
Access points wired back to the main building, once the connection is out there. This is the part that turns a link into actual coverage inside the building.
Why the obvious thing does not work
Almost everyone tries an extender first, because it is the cheap thing on the shelf. Extenders halve throughput each hop and need a solid signal where they sit, so chaining them across a yard leaves you with something that shows a connection and does not move data.
If you have a shop with four bars and nothing that loads, that is what happened.
The timing argument
Metro Loop still has roughly two-thirds of Haldimand to connect. Every one of those properties is about to discover the same gap a few weeks after being hooked up.
If you are in that queue, it is worth thinking about the distribution at the same time as the connection rather than six months later — the work is the same either way, but you get the use of it sooner.