hey there, i would say the nutrient burn is not as big a problem as the fact your plant is root bound , that's because the roots are struggling against the small pot , as well as a bit overwatering that means that you've got root problems on top of the small pot issue. Easiest thing for you to do would be to repot and add a chelation agent like humic acid to your feeding schedule, it will help the plant adapt to its new home by breaking down problem roots as well. Hope this helps ! 🚀