I've got you some insights on how to handle projects, @bsarya-arts.
In QuickBooks Online, you can only assign one donor per project to avoid messing up your reporting.
I advise using a third-party tool for the time being to manage your project with multiple donors.
To proceed, you can visit the QuickBooks Apps site and look for an app that meets your business needs. You can also do this inside your company by going to the Apps menu.
In addition to that, I'll be sharing the following articles to help set up and handle your projects in QBO: