Is it okay if an U7 does not want to play every game?

I would not force him to play. “No substitutes” is there to stop children spending a matchday sitting on a bench while everybody else plays. It should not become a rule that says a six-year-old cannot take a break when they genuinely need one. If he sits for one game, comes back happy and joins in again, that sounds very different from a coach choosing to leave him out. I would quietly notice whether there is a pattern. Is it noise, tiredness, a particular group, feeling overwhelmed, or simply that he occasionally needs a few minutes beside mum? You may be able to make the environment easier once you understand it. The child’s wellbeing comes before making the carousel look perfect on paper.