Hmmmm sounds like my handful!!
You seem to be doing everything right IMO. My handful is 3 now and still struggles with talking. Mom and I have talked about it. She seems ok to leave it for now. It's not my call but I know a lot of his frustration is due to lack of proper communication skills.
Some days are good, some days are bad. He is exhausting some days. Days when I am at the end of my rope he sits in time out longer than usual. If he can't play nice I separate him to the other side of the room.
Keep up the good work!