I just wanted to add that my experience with the call recording feature has also been very inconsistent.
For example, all calls to the same number, with the same network conditions, I get no record button on several calls. So I switch profile, and on the next call the record button shows up, and I am able to record. I hang up, call back, and no record button on several attempts after. I switch profiles again, and the button shows up, and I am able to record. I hang up, call back, and the button is there again. I call back a third time, and it is gone again on every subsequent call.
I try the same test on another phone with GrapheneOS, and the button does not show up until I reboot the phone, then it shows up sporadically, sometimes on outbound, sometimes on inbound.
So the functionality is there, but it does not work reliably or predictably.