Hey there!
Nice to meet you! I'm Darhyl, an Independent Advisor.
Unfortunately, even if you have updated your information to be an adult account, the system still detects that your account is a child account due to its original birth date upon its creation.
The only way to fix this is to create a new Microsoft adult account with a new email address on account.microsoft.com
Note: Ensure that the adult account's birthdate is registered as 22 years old or older.
Once you're done using your newly created adult account, add the child account (your main account) to your Microsoft family as a "family member" by signing your adult account on account.microsoft.com > Family tab.
Note: It is important that the adult account is the "Organizer" and the child account is the "Family member" to make this work.
Once the child/main account is added to your Microsoft family, you can proceed to use the adult account to manage your child account's privacy settings according to the official Xbox website: https://support.xbox.com/help/family-online-safety/online-safety/manage-online-safety-and-privacy-settings-xbox-one#:~:text=Manage%20your%20online%20safety%20and%20privacy%20settings%201,your%20settings%20by%20selecting%20View%20details%20%26%20customize.
"Sign in to your adult Microsoft account at Xbox.com.
Select your adult account's gamertag, and then select the More actions button (…).
Select Xbox settings, and then select Privacy & online safety. Because you’re accessing sensitive info, you might have to enter your password or PIN.
Select the gamertag for your child/main account that you want to manage.
Select the Xbox Series X|S, Xbox One, and Windows 10 devices Online Safety tab or the Privacy tab.
Review your current settings and update these options as "ALLOW":
You can play with people outside of Xbox Live.
You can create and join clubs
You can join Multiplayer matches
You can add friends.
Submit to save your changes.
Then select Submit to save your changes.
Note: You must select Submit at the bottom of the page before leaving or switching to another tab. If you don't submit the changes before you move to the other tab, your changes won't be saved."
Wait up to 24 hours to make sure the changes will be applied.
Thank you for your kindness and understanding! Please let me know if you need anything else.
Best regards,
Darhyl