Hi there, @SB778.

Thank you for joining this thread and providing feedback. Allow me step in for a moment and share some insights.

Currently, setting a default income accounts for different platforms is unavailable. What my colleague provided is the workaround for now. You will have to go through each of the products and services to assign an income account.

I want you to know that your voice matters and I'm submitting feedback about setting default income account on your behalf. Feedback is sent to the Management Team to determine what we need to implement moving forward to provide the best QuickBooks experience. 

You can also do the same. Please refer to this link for the steps: How do I submit feedback?

Leave me a comment below if you have other concerns specific to QuickBooks Online. I'm always here to help you further the best I can. Have a blissful day.