> Dell (they couldn't repair 2 brand new machines that were shipped to us with broken WiFi and took so long to declare it unrepairable

Didn't they use socketed WiFi cards? On every non hair thin laptop I could crack open, I always found the WiFi card to be mounted on a MiniPCI or newer socket, so unless that problem was due to the mainboard, it was just a matter of replacing the WiFi card and install the relevant driver.

Also, if you know how to solder and have a really thin laptop with one available internal USB port, you can fit a small module such as this one: https://www.ebay.com/itm/225197524670 Complete it with a small pcb antenna and you have a new WiFi card. Very useful also for small SBCs which beside the usual USB sockets usually have internal USB ports pins.