Can I switch Enter/Return/Go key to left hand side of iPhone keyboard?

Been having to type on iPhone a lot recently and joint in my right thumb is starting to get painful. One reason is that have to continually bend it to hit Enter key on iOS keyboard.

Anyone know of a method/3rd party keyboard that would allow me to move Enter key over to left (e.g. swap it with "123" key) so I can use left thumb for a while to give right thumb a rest?