So, what is flutter?
Flutter is the multi-platform framework from Google to build apps on any screen. It uses Dart as the programming language (very similar to Java/C# etc.).
From a Microsoft perspective, this is a similar idea to Xamarin or now MAUI.
One thing jumped out to make app designing/coding easy within Flutter is something called Flutter Flow. Worth checking out as it provides a nice graphic UI experience to build apps for desktop/mobile etc. but also provides clean code – not some weird export that you cannot use elsewhere!