It's never about the language, most any language is easy to pick up. However picking up a whole new ecosystem with its associated dev tools, build tools, packaging, and different libraries is where the time consuming portion of new languages come in.
Exactly. When I scanned Dart's language spec, it looked just like any other C derived language. In terms of complexity, Flutter/Dart is no different than Android/Java. When I started writing Android apps, learning Java was the absolute easiest part of that process.
