A lot is going to depend on the exact construction details of the wall. If it's expanded metal lath with plaster over that, then you're going to have a very ha

A lot is going to depend on the exact construction details of the wall. If it's expanded metal lath with plaster over that, then you're going to have a very hard time punching through that with wireless signals -- it's almost a Faraday cage at that point. Otherwise, a powerful directional antenna on the central router plus a powerful directional antenna in the workshop, plus maybe amplifiers, may be enough to punch through. Alternatively, drilling a hole through the wall or otherwise finding a way to string Ethernet cable is likely to be your best bet. The laws of physics haven't changed much in the last nine years. The solutions that would have worked then will probably also work now.