No, that's wrong. VeraCrypt uses AES-NI when available. It seems the source of the issue is the IO design of the driver, which causes unnecessary context switches when operating on a raw device.
On the other hand, trying to backdoor XOR would give you an astronomically higher amount of white noise. Finding important data mixed in with all the other things a computer XORs would be much harder.
If the attacker has access to your computer, you've already lost. If the attacker built your computer, it was never even a fight.