UI is the user interface that provides a good UX that is user experience. Consider for example we have been using radios in earlier days where we have to tune the channels manually. Later on, we had stereo models with automatic tunings. Nowadays we are using voice-overs like Alexa, etc these are all based on the user experience. This makes both UI and UX co-exist. This is also working well for software applications these days. A good UI shows a good way for user experience.