Thanks for reaching out to the Community forum, Matt CND.
QuickBooks Online (QBO) is a read-only app. Once you connect a bank account, it will bring in data based on the transactions posted into your bank account. Thus, changing bank description is unavailable.
In your case, when creating bank rules, you can use the "Bank text" option. This is the description that is coming from your bank.
You can refer to this article for more information: How to set and use banking rules for downloaded transactions.
If you have additional questions, let me know by commenting below. I'm more than happy to answer it for you. Have a wonderful day!