If a civilization is capable of simulating universes, most likely it know if FTL is actually possible or not in their own universe. But it could also be that e

If a civilization is capable of simulating universes, most likely it know if FTL is actually possible or not in their own universe. But it could also be that even the original universe has too many free/independent parameters and the original civilization is as scientifically agnostic as us if FTL is actually technologically possible, so they could say "we thought of everything we could and still cannot prove or disprove FTL, let's create a totally different species and let them have a go, maybe they come up with radically different ideas, but it's better not to create them in our own Universe or they might be smarter than us and turn against us, let's sandbox them in their own simulated universe". They could probably use "A.I." like AlphaGo to try and build structures within their own universe limitations that create Alcubierre drives, but it could also be that that also failed and after searching for aeons, they just raised their tentacles and said "that's it, we're stuck, the only thing left is to try the simulated universe approach".