How do you team team skills and losing?

[SleepingStandingUp]

5 year old twins at first football session
Mixed ages and experience, so mine are def the youngest (one a year older then, rest staggered up to 10ish). 10 in total.
One twin excellent in own team, not good St footie but sociable and trying. Fine not getting ball or scoring. Other an emotional mess, hysterical at not getting the ball, not being with his twin etc.
What have I done different?? Nothing. Sad twin is actually normally the more sensible, independent one.

How do I teach these skills? What an I doing wrong that everyone else is fine and mine aren't? Is it just age? They're in Reception for context

In most countries, we do not thrust our kids into team sports at five or six years old. Get 'em into an individualised sport or fitness activity.

Sounds like a very strange team to have 5 year olds playing with 10 year olds. How are the little ones supposed to get involved?

Isn't there a local football club with a team for each school year group? If so, try there.