Creating a smooth-sloped roof?

Hi - I’m working a project shown below - I’m trying to recreate it within ROBLOX.
I’m struggling to create a decent sloped roof that connect the Outer-rim of the Ship to the roof.
I’ve tried Archimedes and had no such luck. Does anyone have any suggestions?

Mesh or unions, you can make a semi dome with curved parts and then remove the corners with unions or get/make a mesh that fits your requirements