While M-theory is a beautiful theory that would be a Theory of Everything, the holy grail in physics, it makes no testable predictions with our current technology. M-theory testing requires enormous energy scales that we don’t have access to YET.
There’s literally 10 spatial dimensions (M-theory) yet people still don’t in the spiritual realm, heaven, hell, multiverse, etc. It’s astounding to me that people think only what we can see is what to believe.