It's great to have you here in the Community, @userebrecher.
I can share with you some insights on how to manage construction costs plus management fees in QuickBooks Online.
We can utilize the project feature in QuickBooks. This a great way to keep up with your income and the cost of the projects being or been working on. Projects also help you organize all the moving pieces of your project, including transactions, time, and running reports – so you always know where you stand with all your jobs. Connect invoices, expenses, and transactions to each project.
For more information, I suggest reviewing this article for your reference: Set up and create projects in QuickBooks Online.
Otherwise, you can also use other third-party apps in tracking it. We have a lot of supported apps that you can check. Simply proceed to the Apps tab or visit our App Center if it meets your needs.

I've also added this resource to help you learn more about the Project feature in QuickBooks: Projects FAQ.
Please touch base with me here if you have other concerns about managing construction costs in QuickBooks. I'm always happy to help. Have a great day and keep safe.