There are alternative virtual keyboard styles (typically made for use with a mouse and impaired motor control) which would work better. Fewer "fine" movements.
Combined with predictive typing, and you could go pretty far.
Do you have any examples?
Not the OP, but Dasher is a classic example that works very well for a single 2D input like using a joystick: https://youtu.be/0d6yIquOKQ0