I wouldn't make it so I would have to flip a 5G switch and activate the nanomachines or graphene/phosphorene matrices to kill them.
Absolutely not!
Why not? Because then they could still escape if they left the range of the 5G towers.
No no no...
We can't give hope to the slaves. We can't suggest that if they isolate themselves from the control structures that they could possibly survive.
Instead, I would make it so that the kill-switch would automatically activate if they leave the 5G tower area, or whatever remote that would constantly send out a signal ping to them.
That would be a much better plan.
It would guarantee that any of the ambitious sheep who dare leave the "permitted" areas would immediately drop dead. Then, the dumb-ass sheep would immediately associate certain areas as danger areas, not suitable for survival. They'd blame it on the "virus" or "climate change" just like we'd tell them to.
Effectively, this guarantees subservience to big cities and government dependence. Sustainable living will be exterminated entirely. We can't have any rats flee the nest.
Everyone will own nothing and be happy, right?
There are some hold-ups though. Like airplane passengers and pilots getting out of range of the towers, or not being able to transition between signals. Hikers and sportsmen who spend too much time out in parks and nature as well would be vulnerable to low levels of reception.
Frequently dropping signal would eventually result in death, even if the losses are relatively brief, so it's not like there won't be some loss of the livestock in the name of "progress."
I'd consider those glitches in the system, but the fear it generates would nonetheless serve the ultimate purpose in keeping people where they are instead of gallivanting around MY world without MY permission.
This all reminds me of the Fallout games, where slave collars activate when they get too far from the remote and their heads explode.
If you're gonna enslave humanity, this would be the way to do it.
Why not simply destroy people's reproductive systems, lower sperm counts, so that the only way to reproduce will be artificial insemination and assistance of clinics and hospitals.
Now you can regulate who gets to reproduce. If you don't have a high enough "social credit score"... no reproduction for you.
Within a generation, you weed out nearly all of the non-conformists. Within two generations, people get used to the idea of going into a clinic to reproduce. Control education to make sure kids learn from an early age THAT is how it's done. By the time the next gen grows up... they will be programmed to accept going to a clinic (if you have a high social credit score). An added benefit is the fertilized egg can be given all the vaccines before it even develops into an autistic child.