My Canon T6 got wet at a waterfall; the battery did not get wet. I let the camera dry out for weeks - it apparently works now but is giving me totally white images.
Is there any chance this damage can be repaired?
This is almost certainly not fixable without professional skills. Unfortunately, the cost of the repair is also going to be higher than the value of the camera (the T6 aka 1300D was Canon's entry level DSLR in 2016) so honestly at this point your best bet is to purchase a new camera.
Did you remove the battery immediately after the camera got wet and while drying out the camera? If not, electrolysis will happen between conductors and dissolve wiring which will cause the camera to malfunction. Unfortunately, this could be very difficult to fix, and as Philip stated, not economically fixable.
Sounds like water is stuck in/on electric circuitry around sensor.
You want to send it to Canon services for a proper repair, including eventually piece replacement. They will evalutate the repair cost and then ask you if you want to proceed.
This is valid wether you are under warranty or not.