The poster on devrant has joined the discussion and it seems like this is exactly what has happened: they spoke to their neighbours, and their neighbours have refused to make any changes.

It does seem like getting some 5GHz hardware would be a relatively straightforward solution but the poster is unwilling to do that. My take is if you want good quality home networking then you need to be willing to pay the price to get that within the constraints of where you live: sometimes that means spending more money than you might like. Such is life.