Game Center/Multiplayer Restrictions are dysfuncional

Hello Apple Community,

I am writing because I am utterly baffled by the glitches that occur when allowing a child in the family plan to play multiplayer on Apple Arcade. Even though all settings to allow multiplayer are enabled, games just tell us that "This account does not allow multiplayer" or something along those lines. We have spent countless hours speaking to apple support over the phone, and they are not able to provide any fixes/explanations. Before any repliers ask: yes, we have tried literally everything. The senior apple support people have run us through every possible error/setting and nothing prevails. The only clear path now is to try to find a workaround to the settings. We may have to have the child account start on a blank slate by creating a new AppleID in the family plan and have them use that and just lose their progress. That means they would lose their progress not only in games but data in general and it would be a major inconvenience to us. Does anyone know of any other workarounds or anything we could possibly be missing. This post is sort of a desperation call.

Thank you.

P.S. There are other child accounts in the family plan with the same settings where multiplayer works just fine.