Family MS account needing 2 copies of Minecraft?

She should have been linked before (her wallpaper keeps showing up on my PC) and now it's saying she's now joined my 'family'. Is there a way the system has linked someone else with a similar name?

We will validate. Kindly sign in to https://account.microsoft.com/family, you'll see her account from there if her account is linked to yours, you can manage her spending from there.

I have Microsoft 365 with both computers on the licence. I was finally able (I think?) to get her email linked to microsoft (it assigned a name for XBox? Or did it link to someone else's?). I put money on her account to buy the game but now it won't because it says she doesn't have permission (needs a parent or guardian to make purchases) but I can't find a setting that allows me to allow that so I can get the game purchased on her machine for her to play. Would it be easier to just buy it on Amazon because this is way harder than it needs to be.

Hi, I hope you're doing great out there despite the issue that you're experiencing. I am an Independent advisor and I am here to help you in regards to your concern.

For games on Microsoft Store, the license is on the account itself which means that you may need to purchase Minecraft on both Microsoft account.

After you have allowed Minecraft in Family Settings you will need to log out from your MS account in Minecraft Launcher.
Then log back in and your account permissions should be refreshed.