Oh, and another thing, make sure you dont have any security settings with your browser that can impede the CFE website on the router. Brave is good at breaking this sort of thing. Turn the router OFF for a full minute or two and disconnect power before you start the process of entering recovery mode, we need that NVRAM free of junk from the broken upload.
If you miss getting the router into recovery mode on the first try due to timing, disconnect power and wait again before starting over. This sounds odd, but a lot of junk can stay in RAM for quite a while after power off, and youre last firmware is broken so we dont know how thats going to impact.
As long at you are under 100metres , just run cables. Run the outdoor Cat6a variety, or lay regualr in conduit, Dont run just one, run two (One for now and one for later/if something breaks.)
You can buy other point to point wireless netwoking devices as suggested below, but these will all add more power use and complexity as they are a little specialised to get working well.
Cat6a will allow you many years of cheap and reliable service and will be cheper in the long run unless you’ve got some really difficult terrain to work with.
You could also run Multi Mode fibre optic cable up to 550m with 2 cheap swiches that have an SPF port at either end. This will cost a little more, but willgive you near unlimited expansion