Hi @elbutio
You’re spot on - projects would be the way to achieve this. You can tag multiple sales and purchase invoices to a project (which you could use one project per property). This will allow you to produce a profit and loss report for each project.
This should be fine. If they’re a liability for the business, then yes, they should be recorded so it’s on your balance sheet.
This thread is from a few years back, but the concept still remains. Hopefully this will help setting up the mortgage account: Accounting for loans - #2 by Glenn. This thread may also help: Property and motgages - #3 by Ola