I feel like a terrible mother

have a 10 year old whose behavior is so bad. We are doing time outs and taking stuff and nothing is helping. We went to my S/O MOMs for mother’s day and he sat in time out because the whole ride to destinations he would act terrible. And in time out he would blurt and yell words and had a full 20 min tantrum over PUDDING this is an every week I have him situation and his dad even has issues we are aware of divorce can effect things but his brother is totally normal his 2.5 year old sister listens better. It’s like he loves to get in trouble or yelled at. And I have tried the gentle parenting btw. He has severe adhd and adld and I just feel like he may be on the spectrum with other things. Am I crazy