Support partial Guardian presentation/visibility
To reduce the loss of immersion that the Guardian presentation causes, implement limited reveal of Guardian.
Examples of great uses of this are to show specific areas of concern, like areas where the sensors might tell there are risks like walls such as in hallways, or things like dropoffs (detectable via depth sensing).
In a hallway situation, you might want users to be aware of how close the walls are, but not prevent the user from playing in a smaller space such as this. By presenting the walls, and not hiding the hallway, you permit the user to continue playing with some warning of the risks.
This combined with my other recommendation regarding "Larger Guardian areas" makes a compelling argument to support large scale experiences, in a manner that does in fact work with most users actual physical spaces (unlike a single large space).