Technically, everything is stealing and everyone is stealing others work, you might use an open source software, might build your own but uses someone else’s libraries, might take someone’s UI design like OP, someone might use someone’s components, dig deeper and someone is using the icons to build components, dig deeper and someone’s is using a software with builtin tools trained to make similar icons to others, really, there’s no bottom to it. And if you decide to reinvent the whole wheel from the little details, you definitely will have so many bugs and issues, and most likely no one will likes it because it’s fundamentally different than how they are used to use XYZ.