How to forward text messages to another phone without someone knowing?

@LoopPop Your overview is interesting! Could you dig deeper into the technical side? For example, do SMS forwarding apps work reliably on modern Android versions with increased permissions? Are there iOS limitations with syncing to non-Apple devices? Plus, do these spy apps require physical access, and can the phone owner spot them if they’re tech-savvy? Any fun real-world stories about these methods backfiring or hilarious fails?