The radio modems on pretty much all phones* have complete control over the phone, and they can be controlled by state-level actors. So, I hate to say it, but your phone can be bugged at any time. Very similar to the Management Engine on all modern Intel chips.
* There are a rare few phones where the modem is connected by USB, which could (in theory) prevent the modem from taking control over the phone. I don't recall if the modem still has direct access to the mic though, in those cases.
* There are a rare few phones where the modem is connected by USB, which could (in theory) prevent the modem from taking control over the phone. I don't recall if the modem still has direct access to the mic though, in those cases.