The mistake that a lot of people make is thinking that it's a code/framework/tech problem it isn't. Start by putting the technology aside, it only serves to bring your idea to life. Which bring us to the ideas... Ideas are never 100% original. I challenge you to imagine an object of a shape and color not made from anything you've ever seen... it's impossible. What I'm saying is that you need to take inspiration from…
A good framework and set of components can help a lot though. I'm building a mobile app at the moment using flutter, and the material components in that make it so much more efficient to build nice looking things that work well. Animated transitions between screens for instance can be really fiddly, but flutter has support for some useful ones out of the box using 'hero' widgets.