As a former shy kid and introvert, I wish my son was shy sometimes lol instead, he's an extrovert like his father.
It’s just his personality. I was a shy kid. My mom would walk with me up to other kids and introduce me and ask if I could play with them. Then we’d all play with no problem. Maybe he’s better with just one other kid as opposed to a large group, or he just needs a little help and time to feel comfortable.
My boy is an only child too. Can't find many play date things for him. We go to the park and he sees kids amd watches them but he isn't talking either so he doesn't play with them. It breaks my heart that he seems so alone. 😞 he's in Speech Therapy so hoping he'll start talking soon and maybe feel more comfortable to interact with other Littles.
I don't have any advice. But my only child is the exact same way. He's only recently started approaching some kids, but being super awkward about it. I think as long as we keep exposing them and showing them positive social interaction, they'll pick it up. 🤞