Reports

Welcome to flutter. Can you share the code where you are calling the MyDrawer(), I cannot see the overflow when I run it in my device.

For the second error: the problem is that the Image.network in the ExpansionTile.leading doesn't find the image so it shows a error placeholder and that placeholder overflows, you can add errorBuilder:

leading: Image.network(
  icon,
  width: 20,
  height: 20,
  errorBuilder: (context, _, __) {
    return const SizedBox();
  },
),

some other recommendations:

Your MyDrawer can be StatelessWidget instead of StatefullWidget

The use of Material in your tiles seams to be unnecessary

[...] is same as .toList()

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