Welcome to the Community, @bossert-patti,
I'd be glad to help you edit your bank deposit date. If you have successfully created a bank deposit, you can do these workarounds to edit its date.
Here's one of the workarounds:
1. Click the Magnifying Glass icon, next to Help (?).
2. Select View more.

3. Search and filter the specific deposit that you want to edit.

4. Click the deposited transaction, and edit the date.
5. Save and close.
Here's another way to edit your transaction:
1. Go to the Accounting tab, and select Chart of Accounts.
2. Search for the account where it was deposited.
3. Select View register.
4. Click the specific deposit.
5. Edit the date, and select Save.

For more information, you can visit: Find, review, and edit transactions in account registers in QuickBooks Online.
I'll also add an article you can refer to for future use if you wish to add multiple transactions in a single record: Record and make bank deposits in QuickBooks Online.
Don't hesitate to reach us back if you need more assistance with your QuickBooks account. I'm here to help you anytime, keep safe.