If you are using SIGNALS WHATSAPP as a form of secure communication while protesting you should cease and desist immediately. Both platforms have been compromised by state agencies giving them the ability to monitor exfiltrated and record your communications. This is exactly how Hegseth’s chat was leaked.
In addition, if you want to increase the security of your Android device above and beyond the stock Google Pixel OS you can install GRAPHENE OS which is a security focused and hardened platform used by political activists and media researchers throughout the world
(Note: if you are using an iOS Apple device there is no solution since it is a proprietary platform designed to invade your privacy and compromise your security)