[froggy]

Amen. When I read the OP's post, I thought it could have been my manager. I am reserved, not outgoing, but I'm a team player. I prefer to take tasks, especially larger ones and bunker down exactly as you said.

I'm pretty useless in sprint refinements with asking questions in a group setting, but if I'm given a set of requirements or mockups, I'll knock it out of the park every time. Been doing it this way for almost decades now. I didn't snap quit when a previous employer started trying to get me more sociable but I was gone within a few months.

OP would be well-served to take your suggestions if they want the developer to stay.