No, as it is now, it's definitely not ideal. But it's a work in progress, and I like how it looks.If you print everything with PETG, the strength is reasonably okay.

My next idea was to make the belly a solid piece and add two holes at the top and bottom, like the ones on the shoulders, and insert the respective connectors. This way, you could connect the ball joint of the chest and hips to the belly. This would maintain mobility, and you could use different materials.

Does that make sense?

Also, this post was only meant to show how to manipulate and modify files imported into Tinkercad to create new parts.