I believe what you envisioning requires more reliable communication to Apple's servers. Perhaps an Apple Watch with a LTE/5G connection. The Apple Watch already has a feature to alert emergency services in case you "fall" or involved in a car crash. The hard part is teaching non technical folks how to use the Apple Watch. I know several seniors who would benefit from this technology but I hesitate to recommend it to them because they can't even figure out their iPhone despite owning one for 10+ years!
https://support.apple.com/guide/watch/contact-emergency-serv...
Then again false hope sells. Might be a good business plan but end up lacking in practicality.
I think a device that you can use to take a picture of an approaching suspect's and it uploads it to an online database - available to the police and friends - with your location would be more of a deterrent - if it's usage was known to perpetrators.