Professional designers, whether Industrial, Graphic or UI, borrow all the time from each other. Design is mostly derivative and commonly based on inspiration. Design is not Art. Art is communication to self, Design is communication to others. Big difference. Copying Art is stealing. You can legally copy most designs, unless there is a design patent filed which explicitly defines the parts unique to it (design patents are very hard to protect).
Others use designs as inspiration. Even Apple has very strong derivative designs as pointed out at:
https://www.apartmenttherapy.com/apple-design-doesnt-fall-far-from-brauns-tree-176668
Young designers can learn a lot about proportion, contrast, color, and aesthetics by actually coping designs they like. In grad school, I used to copy Syd Mead’s work, brush stroke by brush stroke, just to learn composition.
It’s easy to use other work as inspiration, and once you know the design rules, you can make changes which will make it unique to you. I have told students NOT to start with an empty canvas, but instead find something that inspires them. Mood boards (look it up) are used specifically for that.
You not need feel guilty being inspired by other designs. Professionals do it all the time.