Why are you using PCTPE for a T-rex model? PLA or PETG would be much easier, and for a model, anything besides PLA doesn't make much sense unless you are making outside sculptures or something. PCTPE is known for heavy warping and although its strength is impressive, it's considered engineering grade filament. Meaning, unless you need the material properties of PCTPE, you are wasting money and time trying to get it to work. In your case, you have splitting at the higher levels mostly likely due to the thermal gradient (bottom of your print is very hot due to heat bed, top is considerably cooler). If you wanted this to work you would need a completely enclosed chamber and ideally a way to monitor the temps at different heights.