Good evening, @david5420.
Thanks for coming to the Community with your question about moving your data.
There isn't a way to import the backup file of QBDT to QBO. However, I recommend using a trial copy of QuickBooks Desktop or re-upping your old account to ensure you get the data over to your new QuickBooks Online.
Download a trial of QuickBooks Desktop
I hope this helps answer your question. I'm only a reply away if you need me. Take care!