I accidentally spilled some soup into my MacBook Pro keyboard 3 weeks ago. Some keys seem to behave totally wonky now. How can I disable the native keyboard, so I can use a USB-C keyboard?

My Baby... my MacBook Pro 16" is behaving insane. I usually use an external USB-C keyboard, but I am discovering the hard way that if you spill soup into your keyboard, even if you use a separate USB keyboard, the native keyboard can still cause all sorts of chaos. For example, one of the modifyer keys, "control, option, or command" will spontaneously become active and the computer will behave as if I have my finger resting on that key. For example, suddenly everywhere I click will seem like I am control + clicking (right-clicking), and I can't "shake it." I can tap the control key a dozen or so times, and am sometimes lucky enough to un-stick it. But usually, I end up having to restart. And this is happening hourly... so it is a 100% soul-crusher.

I cannot seem to find a way to disable the actual MacBook Pro keyboard, so that the computer does not even "see it," when I am using a USB keyboard. All online articles I've been able to find make references to "preference" settings that are now outdated, and no longer seem to work.

Can anyone help me figure out how I can kill the keyboard on this MBP 16"? on Ventura - 13.2.1?