Also, if you wish to go back to Quicken from QBO, you may check this hyperlink: Convert a Quicken file into a QuickBooks Online company file. This article provides you detailed steps in converting files from Quicken to QBO. It also informs you about the rules you need to set up in online banking to update transactions once the import is finished.
I'll be here if you need anything else. Stay safe and take care always, cicenhour.