Depends on the risk your at. If you’re in a country where having your own opinion is dangerous (Russia, for example) it’s certainly different to a person in Western Europe.
tbh I always assume a government has the resources and access to generally undiscovered or unfixed vulns, modem firmware is just full of holes. many layers of legacy code and the least amount of eyes going over the code. you can’t win against the government on a phone like this.
when this is a concern, maybe use a laptop or tablet, with wifi connection to a hotspot device that doesn’t have a mic.
what made you choose that distro?