You would need to educate the masses first on how to use this stuff. And you end up sort of carrying an active beacon around. Which probably isn't a great strategy if you want to hide in plain sight of people empowered to just shoot you on sight.
Most phones don't have a huge range in any case. So, covering a wide area with a mesh network would be very vulnerable against repression. Just take out all the nodes that you can detect. If your phone picks them up, the suspect is within line of sight probably.
Technology has very few answers to repressive regimes like this. Mostly people get afraid and refrain from using the things that might get them in jail and self police. That also breeds trust issues. The DDR regime ultimately got children to rat out their relatives. Modern repressive regimes are learning from each other as well when it comes to identifying and neutralizing pockets of resistance. The Bangladesh playbook was perfected by the Chinese, Iran, Myanmar, etc.
Usually those regimes only end when people get hungry and angry enough. As long as you keep the economy going, regimes can last a long time. And of course North Korea perfected the art of repressing a starving nation. So even that is not a show stopper.
We're not at zero risk of regressing into living under oppressive regimes like that. I live in Germany where the scars of communism and fascism are still very visible. It only takes some rogue fools to win an election to roll back the clock a century.