Yep, the vast majority of lease to buy deals go sour. It’s not a good deal to overpay your rent, lose your security deposit (down payment) and often more. You’re better off renting.
Years ago I worked in the mortgage loan assumption department of a bank. Assumption as in someone buys your house and assumes the burden of your mortgage loan.
I saw many a heartbroken young couple lose their nest egg in one of these agreements and then the seller just went out and sold the same house again.