Hello! My name is Ben a fellow member here in the community, not a Microsoft employee. Hope you are doing well!
With regards to removing the restrictions from your Microsoft account. If your account was previously added as a child or member, the parent or organizer account needs to remove any restrictions first before you leave the family group.
I suggest to add yourself back to the family group first as a member and have an organizer or paprent account remove the restrictions first. You can ask an organizer or parent account to add you here:
https://account.microsoft.com/family
Once you are added as a member, ask the parent account to manage the restrictions on the same page and remove everything before you leave the family group. You can also refer to the Microsoft page here:
https://support.microsoft.com/en-us/account-bil...
I hope it helps. Have a great day!