Disability benefit

Did you receive this benefit as an employee? Then it's from your employee status. I don't think it will have any impact on your accounting.

Employee? No, as a self-employed sole proprietor.

I would think somewhere as income for your sole proprietor? But I'm not sure, maybe someone else in the community can help?

Via reports >> start income statement >> you can enter something there without a document. Maybe you can add some "turnover" there, because that's what it seems to be.