How Can I Create an AppBar That Looks Like This:

How could i achieve such AppBar,The AppBar itself does not have to be an actual AppBar widget.

if it can be done with a normal Container,Painter or ClipPath I'd still appreciate it.

Does not have to a SliverAppBar either, no scrolling effects are mandatory.

Here's the widget:

Padding(
      padding: EdgeInsets.symmetric(horizontal: 20 , vertical: MediaQuery.of(context).padding.top),
      child: ClipPath(
        clipper: SimCustomClipper(),
        child: Container(
          color: Colors.blue.shade600,
          width: double.infinity,
          height: MediaQuery.of(context).size.height/3,
          child:  Padding(
            padding: EdgeInsets.symmetric(horizontal: 20, vertical: 50),
            child: Align(
              alignment: Alignment.centerLeft,
              child: Column(
                children: [
                  Text(
                      'Manage',
                    style: Theme.of(context).textTheme.titleMedium?.copyWith(
                      fontWeight: FontWeight.w500,
                      fontFamily: 'TimesNewRoman',
                      color: Colors.white,
                    ),
                  ),

                  Text(
                    'My SIM Plan',
                    style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                        fontWeight: FontWeight.w300,
                        fontFamily: 'TimesNewRoman',
                      color: Colors.white,
                    ),
                  ),
                ],
              ),
            ),
          )
        ),
      ),
    );

Here's the clipper:

class SimCustomClipper extends CustomClipper<Path>{

  @override
  Path getClip(Size size) {
    Path path = Path();

    path.moveTo(0, 0.6*size.width);
    path.lineTo(0.33*size.width - 20, size.height -15);
    path.quadraticBezierTo(0.33*size.width+5, size.height, 0.33*size.width +30, size.height - 20);
    path.lineTo(size.width, size.height /3);
    path.lineTo(size.width,0);
    path.lineTo(0, 0);
    path.close();
    return path;
  }

  @override
  bool shouldReclip(covariant CustomClipper<Path> oldClipper) =>false;

}

btw, according to that clipper, you should make these fixed values eg : 15 ,30 ,...etc flexible to be responsive.