Do not bring your phone with you to a protest.
If you really need a phone on you, get a burner phone with a prepaid card not linked to your person. But remember, MITM attacks are possible and the police can intercept your traffic and in some cases even compromise your E2EE services (if the key exchange takes place on a compromised spoofed network, see stingrays [1]).
If communication is necessary, get a meshtastic device. It’s not the most reliable, and the channels can be jammed, but no one will bother with that. Because they work on usual IoT/smart home appliances frequencies, there is so much interference in cities that triangulating your position in a crowd of people isn’t very realistic.
[1] https://theintercept.com/2020/07/31/protests-surveillance-stingrays-dirtboxes-phone-tracking/
Terry A. Davis popularised the term. He was a software engineer that ended up with a very bad case of schizophrenia. While unemployed due to his illness, he streamed while working on his own operating system that he built with the intention of “communicating with God”. While streaming, he used to go on these rants about how federal agents are spying on him, calling them “glowies” more often than not along the n word with a very hard r at the end. The term “glowies” has very racist associations.
In other words, you need to be somewhat fairly far down the alt-right pipeline if you actually talk about “glowies”.