Platforms vary a lot in how much they verify, rigging, and their diligence is not a substitute for yours. What to ask for, in the words that tend to get an answer:
A full realized track record, meaning every deal the sponsor has taken from purchase to sale, with the hold period and the actual realized return to investors, including the ones that lost money or returned less than projected. Forty projects with three case studies means 37 you haven't seen. If the answer is that most are still open, that's useful too, because a sponsor with a long list and few exits hasn't yet been tested by a sale.
The sponsor's role in the prior deals. "Transacted" is a loose word. It can mean they were the general partner making decisions, or that they co-invested, or that a principal worked on it at a previous firm. Ask which.
Whether the sponsor has ever missed a distribution, called capital after the initial raise, or handed a property back to a lender. A straight answer to that question tells you more than any case study. An evasive answer also tells you something.
The piece people skip is asking to speak to investors from a completed deal. Some sponsors will connect you, and hearing how communication went during a bad quarter is worth more than the projections. And if the offering page and the actual offering documents describe the fee structure differently, the documents govern, so read them before you decide anything.