Hello @KAYLAKONCIERGE !
Newly ceated Facebook Business Manager did not integrate with Shopify it needs to be old because its gives the gesture that new business manager is created only for this business purpose which give indicator you are a rookie in business. It is better if it was a personal account that was up and running beforehand, as they need to verify that you’re a genuine person. A new account that is suddenly handling a business account looks suspicious.
Hope this helps!