Stuck key
One key is stuck.
So it gets pressed by itself
Hence cannot use keyboard efficiently
In addition to the above, you’re headed for a hardware repair.
Use the Contact Support link in the upper right.
The folks at Apple can discuss your options and alternatives.
A temporary work-around is attaching a different, external USB keyboard.
Attaching the second keyboard is also a good test, to see if there’s some screwy software intercepting the key.
