Or have a hands-off policy like we do with uncontacted tribes and some protected animal populations etc.

I'll settle for anything to be honest. A sign, a derelict, an artifact, a fossil, an echo.. anything to distract humans from shitting on each other for a little while at least.

Again, physics says they can't. relativite and signal degrigation is hard. the energy of a star outside our arm of the galaxy isn't easy to detect, much less any signal of lower power.