If they had that, they’d no longer be FOSS and instead “source available” and half the community will raise the pitch forks. Best FOSS licence to protect against this sort of thing is AGPL because it’s toxic for corporations. But even that could be used in this case if they had the source on the same computer imo (IANAL though)

My personal recommendation is only one at a time though

You wouldn’t do this if it weren’t profitable. The tenant will end up paying for the furnishings and maintenance many times over in rent, and you will get an appreciating asset that you are gradually paying off the debt for. You’re not getting paid for management, you’re profiting from holding capital in a system designed to benefit those that have capital, and seeking rent for the ownership of that capital.

I wouldn’t hold it against someone in this system we have if they end up buying a property to safeguard their money, but let’s not pretend that landlords are not a parasitic relationship that reduce the amount of housing stock available for people to buy and act as a middle man between a tenant and a property management company.