Though it isn't required to have your online bank(s) connected to QuickBooks Online (QBO), you'll enjoy a certain benefit from doing so @mjdunn15.
I'm referring to the feature of having your online bank transactions automatically downloaded to your QBO company. This saves you time, instead of entering those transactions by hand. This leads to you having more time to handle your business and less in managing your books.
If you want to proceed with disconnecting your online bank, see this article for the steps: Disconnect or delete accounts connected to online banking.
Another option is to bring bank transactions into your QBO company via a CSV file. View this article for the steps: Manually upload transactions into QuickBooks Online.
In case you bump into issues while uploading bank transactions, keep this article as a reference: Fix bank upload errors in QuickBooks Online.
Feel free to hit the Reply button and post a comment below if you have other questions about online banking in QBO. I'll be around to help you out.