No. As the name implies, User Experience means everything affecting the experience of a user, digitally, physically and mentally.
Every problem, experience, etc you encounter can be cut into segments with a start and an end depending on scope. Everything that happens within that start and end is your user experience for that specific segment.
Zoom out enough ...
There’s a lot of different opinions about this.
Some people will say UI is how it looks and UX is how it works which is a bit off the mark.
I think of it more as follows:
Interaction design is about designing user interfaces (UI) that users can use. How it looks and how it works influences this. For example, a legible font makes an interface easier to use. ...