Thank you for reaching out to the Community. Most financial institutions allow both nightly downloads and manual updates. However, American Express accounts are slightly different.
Some American Express limits the frequency of automatic downloads, so QuickBooks Online may automatically download your data 2-3 times a week instead of every night. However, you can manually update your account between automatic downloads.
We can manually update bank feed to download all the transactions. Let me show you how:
Click the Banking menu, then Banking.
Select the account you want to update, then click Update.
For security reason some bank requires authentication, then enter your Multi-Factor Authentication (MFA) credentials. Then tap Continue update.
You'll get notification once update is successfully finished. The number of transactions in the blue account tile will increase if QuickBooks downloads new transactions.