Hello
Does your business account currently have other Microsoft business tier products?
If not, in Microsoft's eyes, it is still a "personal" Microsoft account, and as long as you subscribe to the Microsoft 365 personal or family plan, sharing should be fairly easy between two accounts - you just cannot merge them.
However, if your business account has some Microsoft business tier products, then Microsoft sees it as a "work or school" account, which is a completely separate ecosystem from the personal side of products. You will not be able to get the Microsoft 365 personal/family, and sharing/configuration can run into challenges.