In fact, the process of interaction can be patented, and now many patents are aimed at solving the user interaction experience. The most important thing is to see how you write. If it is not well written, it is easy to be considered that the business method has been rejected.
You can't apply for a patent for UI interface yet, but a patent for UI design has been added in the recent patent implementation rules, and it is estimated that it will take another year or two to apply.