There is essentially no historical evidence for any of the Roman founding myths, at all. There are a few ruins near the forum that could have been a royal palace or similar structure, but that's about it. Almost everything we know about early Rome comes from Roman historians writing centuries later. Livy is perhaps the most influential of these, and he wrote about 700 years later, around the year 30 BCE. He was essentially retelling stories that had been passed down over the centuries, so while they might be true, there's absolutely no way to really know.

The truth is, we can corroborate almost none of Rome's early history. Mostly we accept the Roman historical accounts, but those are obviously products of a very different academic construct; one often fused with mythmaking and allegory and often colored by the contemporary politics of the writer. It doesn't mean Lucius Junius Brutus didn't exist, but we don't have any compelling reason aside from the myths to believe he did.

If you're curious about early Rome and what we know for sure, check out Mary Beard's excellent SPQR. She covers all of this in exquisite detail and is very upfront about the limitations classicists face when dealing with Rome's early history.