This creature right here is one of the decedents of placoderms that that transitioned from rivers to land. The got onto land during the Middle Devonian and remained isolated from all other land animals. The only non-placoderm descended creatures are arthropods, amphibians, and a few species of birds.
They have and spine, skull, a few ribs, flexible stringy organ support structures, and ball and socket joints for their exoskeleton. The exoskeleton is all over the outside except for in the joints and supports most of the creature. The joints are all endoskeletal and ball and socket joints covered with muscle and leathery skin. They have six legs and walk similarly to insects buy having three legs on the ground while walking. They don't molt their exoskeleton expands like sea urchins do and they don't even develop the exoskeleton until they at least halfway don't with growing to their full size. They are about 30% larger than a Paraceratherium ans weigh in at 45-57 tons.
Based on how this creatures anatomy works could it physically sustain the weight and height it is at, and if not what are the minimal changes I can make to allow it to be at this size and weight?