I've noticed the first answer, just wanted to include a direction for the remaining parts.
Yes! A UV sphere is the best way to approach the big round part.
No Geometry Nodes are needed for this model.
Similar but slightly different approach is to use Inset on the face strips instead of Extrude
The front part can be modeled using Curve with Bevel Object, a Circle for the disk and star part and subdivided cubes for the two plates.
How to inset Face strips:
Select the odd columns of strips:
press "I" on your keyboard to invoke the Inset operator. Adjust the operator settings and add a Depth in negative direction:
Select the even columns of face strips:
Press Shift+R to repeat the last operation with the same settings:
Here is a screenshot of the Crown curve and the applied profile curve:
This is not a tutorial how to model a helmet but a guide on how to approach it.
Here is a .blend file with the model shown in the screenshots above.