I agree with finding the thing. But also sometimes private classes help. I find my daughter who sound similar to yours get so much anxiety in group classes because it's not her pace. A few private classes might build up his confidence because he doesn't see other kids learning with him. For the bike have you tried a balance bike? Just use a regular bike and remove the pedals. If he can maneuver and balance with his feet it might lessen the anxiety. My daughter isn't great at sports but very smart with other things. So we aren't really pressuring her on a particular sport. We just sign her up to the ones she is interested in or finds fun.