Well there's plenty of precedent for employers and schools mandating that employees and children respectively get vaccinated. The main difference being those were all FDA approved, and as you say, we're potentially going to mandate taking emergency authorized experimental drugs.
You'd probably know better than I, but wasn't there a massive controversy over experimental smallpox vaccinations on members of the military? Might be some interesting precedents there that can be applied to civilian life.
Security exists on a spectrum and Signal is somewhere in the middle. You do register with a phone number, so other Signal members with your phone number will become aware that you use the service. I find that problematic but they're working to divorce Signal from phone numbers altogether. It's taking a long time though.
Your messages are end-to-end encrypted. They're open source and their systems are audited by privacy organizations. If you're really worried about it get the APK directly from the source, compile it yourself, and install, vs getting it from the Play Store.
Meta data is exposed. Snowden always said it's the metadata that really counts. But I'm not exactly texting with domestic terrorists, I'm just texting stupid 4chan memes to my drunk friends that will get automatically deleted within 24 hours, stuff I don't want to see surface during a job interview someday.
It has its flaws, but there isn't really a perfect platform. Anything has to be better than SMS, which is staggeringly unsecure.
I started masking when BLM violence broke out because everyone hated each other, I wasn't sure how badly violence would spiral out of control, and I didn't want to be a target. Now I refuse to wear it, I don't care if I'm a target, they can fucking gun me down in goddamned Kroger I'm not pretending anymore just to make them happy.
Amazing what a year of lies and propaganda can do to a person.
I wish I had a family