I think I have found the other piece of software I was thinking about. It's called SaasAnt Transactions (https://www.saasant.com/)

It's usually used more for importing and has a better price if only using it for short term. (Although it looks like you can do Transaction Importer Pro on a monthly basis now for QB Online)

Between Transaction Pro Importer OR SaasAnt Transactions, you should be able to migrate your data. I would start with TPI first since there's already an actual write-up/walk-thru. You could also call SaasAnt on Monday and figure out if they have the ability to migrate/transfer/copy between 2 QBOnline company files.

I also sent you a private message.

The struggle is real, hopefully rewind will bring back that function as well.