I too have knocked off a component from the underside of my Pi 4 board, a result of a poorly designed case. I could use help to identify the component. As I am dyslexic reading a schematic sends me around the block a few times. Just looking at the board I am assuming that the part is a resistor and having to do with the Wi-Fi circuit. Attached are pics of the problem. Thanks for any help from anyone. ----------
There are no schematics published for the Raspberry Pi. Only reduced schematics are available, which show connectors and parts of the power distribution circuit. You won't find that resistor in there.
From the looks of it this could be a pull-up / pull-down of some sort. If I had to do this without any schematic, I would solder a 100 kOhm resistor and see if the board boots up. If not, I would then try 10 kOhm, 1 kOhm and finally 100 Ohm, and if none of them would work, I'd get a new board.