One issue is that there is "one Intuit ID" for all the portals. I also don't know how you started that tax return, such as the link from QBO or only through the ProConnect portal. And I don't know if you log in through the QBO Accountant Portal, and see only QB clients, or all your clients including tax. I log in using the same ID everywhere, yet some show me different perspectives and listings.

In general: "unless she gives me back access to QBO, which in my opinion should not affect access to tax returns."

This answer assumes you didn't File the return and you have no file copy and the client never got a copy. Have her give you that temporary invite, use it to get the info you want to hand off, then have her remove you, again. Also, perhaps what she asks for isn't something you want to or intend to provide. You don't have to give away your own work product, if you were not paid for it.