When you say "isn't 'lit up,'" do you mean is greyed out? If yes, I can't guarantee a fix, but see:
Why is my Apple ID setting greyed out on iPad? https://discussions.apple.com/thread/8355468.
A post in this thread says: "I just found the reason for my Apple ID Settings being greyed out. When I disabled Restrictions, my Settings became enabled and I was asked to update Apple ID Settings. S O L V E D..."
Apple ID banner grayed out https://discussions.apple.com/thread/8611970. This one reports a similar solution having to do with restrictions.
My Apple ID is Greyed Out in Settings, Fix https://macreports.com/my-apple-id-is-greyed-out-in-settings-fix/
Note that these documents tie in with Eric Root's question above: Have you checked Settings/Screen Time for any restrictions?