I’m just gonna leave this here: https://valetudo.cloud/

Other bluetooth devices in your area

Mapping like that is probably mostly done through bluetooth and wifi triangulation.

Sure. Including pictures of people shitting.

Always have been.

That was actually one of the reasons for Java becoming popular.

Most Apps are just Java/Kotlin code, which is converted into your CPUs instruction set at runtine.

So usually this will not be a problem. Unless you use some kind of hyperoptimised App, which should be rare.