Take a look at the cpu and the gpu, the heat-conducting paste no longer works properly when it gets wet. Also look under the board, it could be that there is still some liquid residue. Good luck
If an M.2 interface is available, you can use it, if not then you can swap the old HDD for an SSD from WD Blue, then install the operating system and then you can get started.
Unfortunately, Apple is not a fan of self-repairs or repairs in general, they code all their devices with the individual parts and a replacement that you do yourself would deactivate some functions and the parts are far too expensive and just so that you buy a new one. In and of itself, it's only worth it if you really want to keep your macBook.
Update the Oculus, reconnect the cable and see if you have plugged the oculus into a USB 3 port, it would be best if you update your graphics card and windows and switch off the power saving mode . Maybe it helps