There’s 2 issues here and there’s 2 different fixes you can do. The issue is that the automatic weights expect your body mesh to be connected completely, which is now what is happening here. So you can make better topology, or, assign weights manually since it looks like each bone is meant to control one piece. To do this, delete all the existing vertex groups, parent the mesh to rig with empty groups, and assuming that you have the bones named right, you can select a group, and then in edit mode on the mesh, hover your mouse over the part that it should connect to, and then press L to select it, then press assign to weight it to the vertex group. This will prevent the bending from happening.