Baby is behind?

My little bean will be 1 on saturday (Dec. 5) and I feel like he is behind. He began walking at 10 months old and has always been ahead physically. He also showed good brain development since he met those milestones early too. He knew how to say mama at around 6 months old but then stopped and didn’t say it again until 9-10 months and he only says it when he wants me. If I ask him who am I or ask him to say it, he won’t. He also knows what things are but doesn’t wanna try saying them. And I’ve tried to sit down with him to try and learn stuff but he’ll get uninterested quickly and go play with a toy. I taught him the cow says moo and it took me a while to get him to actually say moo and do it on command as well as when I tell him to dance, and he also knows what No means but shakes his head rather than saying it. And most recently, if I tell him to find the ball, he’ll go to his book and try to find the page with the ball but that one is also a hit or miss as he sometimes doesn’t want to as well. My pediatrician says she doesn’t think he has a learning disability she just thinks he’s a more difficult baby to teach since he’s stubborn and doesn’t do what he doesn’t want to most of the time. But I just don’t really know what approach or activities I can do to keep him engaged and to actually teach him new things since he gets bored and frustrated easily and doesn’t do anything until he’s 100% sure he can execute it. But at the same time, if he doesn’t try he won’t learn 🙁. I feel like I’m failing or like I’m out of my league since I have no clue how to cater to his specific personality. Help!☹️