But what makes leveraging those existing designs so effective isn't simply seeing and copying them (that'll do in a pinch, but ultimately may lead to misuse).
What makes standard patterns from platform sources so effective is that you don't have to wonder whether they'll meet your needs or not: they're already standard, customers will understand them, and if you're so inclined you can look behind them to better understand their rationale via material.io for example.
But, again, without understanding what you're copying you're likely to run into small problems. Such as: when should you use a modal dialog over a sheet? When should a button be hollow vs. filled? When to use radio buttons vs. checkboxes? Should a transition animate from the bottom, left, or right of the screen (and how do those each help the user orient themselves in the experience)?