Welcome to the Community, @PINLINE. I can provide clarification on using Projects.
Since you've referenced usage limits, I wanted to take a moment to let you know that inactive Classes will not count against usage limits. Should you have old Classes that you're not using, this would be one option for freeing up some space. For additional information on making them inactive and usage limits, please see the following articles:
While there currently isn't a way to automatically convert Classes to Projects, you can manually assign the transactions to a Project. I recommend the following article for insight on this feature: Set up and use the Projects feature.
Please also know that QuickBooks Online Advanced doesn't have any limits on the number of Classes that an account can have. This is in addition of other version specific features, such as Smart Reporting with Fathom and Simple Import Tool for Batch Invoices. You can read about these and more at the following link: QuickBooks Online Advanced Overview.
Should you have questions about this information, you can always find me here. Have a good one.
