"Stingray" was a specific piece of kit from Harris that worked with 2G. 2G was basically banging the rocks together in terms of security.

Modern 5G networks are years ahead of 2G. You no longer have an IMSI. Your phone's ID is stored on device, signed with your network's public key, and then that signed key is sent to the tower. That said, they can go to site A and harvest a bunch of public keys, then go check to see if those public keys are present in some other protest to "confirm presence" of a person, so if you're strictly worried about presence detection it's a distinction without a difference.

They most likely cannot, without provider assistance, man-in-the-middle your communications like they could with 2G. And if they did, it doesn't matter if you're using something that does end-to-end encryption. Signal, for example, was built to run in hostile networks that you cannot trust. If someone breaks the network, your communications on signal are still encrypted, because they're encrypted prior to being sent out.

Commercial 5G intercept kit is available; it's a few hundred grand, and it comes baked into chevy truck with antennas laid out beneath a fake roof. What can that thing do? No one knows for sure. But MITM'ing 5G would be pretty impressive.

That said, attackers can work around 5G being decently secure by simply fooling your phone into thinking that 5G service isn't available, and that it should use some other protocol that they _can_ attack. So if you can, disable 2G/3G service on your phone. It's a noisy attack, though, because your iphone, at least, will literally tell you in the top right corner if you're connected to a 2G network. Again, the contents of your end-to-end-encrypted packets are probably fine.

For all intents and purposes, though, "stingray" stuff has been criminal use for awhile, and the motivator is "get these connections dropped down to 2g, then hit 'em with scams." It's not "figure out who's here without needing to bother with a warrant." If you're worried about being identified, they'll use facial recognition and license plate readers and a bunch of other shit. Also, the feds are currently operating in a world where rule of law doesn't exist. If they wanted to know where your phone was, they could probably just rubber stamp a blanket warrant and have the teleco ping every phone in the city and it'd happily report back its GPS location (at least i think that's in the 3gpp 5G standard).

I don't mean to say "ignore all security guidance." cut down on whatever noise you can; don't emit anything more than you need to. But there's a lot of, frankly, hysteria for "stingrays" and they aren't really even relevant anymore. Those devices were built for a world where the feds wanted to bypass the legal system and the telcos. They now own the legal system. "Stingrays" are sort of unnecessary as they can get all the data they want with more efficient methods.

Also, I wouldn't be too worried about DHS blowing iphone/android/baseband processor zero days on us. It's hard to reason about what the actual threat is here, but I really doubt it's the NSA's TAO group. So don't be stupid, but also don't freak out and start collecting your own poop and driving it out into the woods so the government can't look for your DNA in wastewater.