I need advice 😅

Jullz ☀️

My son has now entered a phase where he wants to be like his little sister (who is 9 months old) He is fully potty trained but purposefully wets himself/refuses to use the toilet, constantly tries to steal his sister’s pacis, toys, bottles, etc. Wants my attention 24/7, complains whenever we pay attention to his sisters... please tell me it’s just a phase 😬 What can I do to fix this?