Is UI harder than UX?

I often hear people debating whether user interface (UI) is harder to design than user experience (UX). So, I'm curious to know your thoughts on this. In your opinion, does UI pose greater challenges than UX, or is it the other way around? What specific aspects of UI and UX make one more difficult to master than the other? Additionally, do you believe that the difficulty of UI and UX design varies depending on the industry or project? I'd love to hear your insights on this topic.