The way Microsoft accounts work is almost completely opaque to users. I’ve been in similar scenarios — the switch directory or switch organisation technique usually worked for me - but wasn’t enough for this person. They never really give you enough information to tell what’s going on… maybe it’s a security risk to have consumers who are anything other than bewildered Kafkerian characters struggling against a faceles…
Try having a kid and segregating funds for them while paying for their Xbox Game Pass and a Minecraft Realm with your account. I have 25 years of Windows software development experience and I was almost reduced to tears just trying to understand what I'm even trying to accomplish. Realms is still in some kind of half subscribed, half not subscribed state and it still asks for my account's PIN for purchases but actual…
Also parental controls seems to suck in general on most services. Nintendo Switch seems to get it right for the most part.