Your best option is to run a cable out to back, I have the same problem tried many things, run a business from the shed and internet always been a problem but sorted with a wire ran all way out back.
The other way I temporarily ran it was buy using a sim into one of those netgear wireless hotspots and pay monthly for the data required, but make sure it’s a good network which covers your area otherwise back to normal.
The other way I temporarily ran it was buy using a sim into one of those netgear wireless hotspots and pay monthly for the data required, but make sure it’s a good network which covers your area otherwise back to normal.