I have two Apple ID’s and a family of 7 - Help

He is my dilemma. We have triplets that are now adults. Back when they got iphones (circa 2013) My original Apple ID (which was first used for Itunes pre Apple ID and is a Yahoo account) is the ID used by me on my iPhone. Then when Family Sharing was introduced I created a new Apple ID that would be my personal one (its a Me Account) So my Yahoo account is used by all 6 of us for media and purchases. Its worked well, but in hindsight it was a mistake to do this. This set up was recommended to me way back then by a Apple Store Genius. But my wife and I had another child who is now 9 and has an ipad and will have a phone at 13. The ipad is set up on my wife’s Apple ID which works but is obviously not ideal. I wish Apple could allow a family to request a 7th Apple ID or have a process for those with large families. I understand there needs a limit but wish they had a process in place to allow expansion.

I think my options are to kick of of my kids off (what would the ramifications of that be for them), or to delete that original Yahoo ID and move everything to my ME account.

I have talked to Tier Two Support about this

but not anyone who could outline the process flow to do this. They did acknowledge there are quite a few people set up like this but didn’t know the best way to fix this. I just would rather my 25 year old address not be my Apple ID going forward. All of the Apple music, movies, Apps, etc.

i am hoping posting this, someone can assist me in this process. Thank You.