The 16" Recoils look really really nice - You can get one with a 4090, 16GB PCS Pro RAM and a 1TB P41+ for £2,469.00 (No Windows key, Gold Warranty)
I would recommend getting the Gold warranty, and you can pick up Windows keys for cheap online.
They have recently introduced an in-house repair team that can deal with specific board related issues, but the vast amount of RMA reports you have physical access to must say otherwise!
It should be a plug-in, not soldered.
I'd recommend unplugging it and taking some photos of it and sending them through to PCS, the images may help them locate the part.