Thanks for bringing this up, SteveMcG.
Currently, AMEX is not supported on a direct connection to QuickBooks, though we are working closely with the bank to have this implemented in the coming months.
You can keep your eyes on our Community article linked here which will be updated as soon as the connection is available.
Alternatively, you can upload your transactions to the Banking page.
Then, you can start assigning, categorising, editing, and adding downloaded banking transactions.
Get back to me if you have other concerns. I'll be around to answer them all for you. Keep safe and have a good one!