Can you copy UI design?
Yes, there is no issue in copying other similar app UI structures. I will tell you why! There is a reason why experienced designers copy their competitor's UI layouts. Due to this very foundational law in UX, It's a safe bet to go with your competitor's UI layout.
Where can I find UI design examples?
Where can I find good UI design examples? Dribbble is the best web page to view tons and thousands of UI design examples. You can use the search bar to find good examples based on your industry or preferred style.