No phone signal when traveling internationally

No phone signal when traveling internationally for 5 days. Brazil.

I’ve tried manually selecting networks and multiple restarts. Also tried an alternate device.

data roaming is on and I even added a global pass on the advice of a support agent.

It’s worth mentioning I’ve had a very bad experience with multiple chat support team agents  - there seems to be a certain unfamiliarity with an approach to troubleshooting and they keep asking me to upgrade my plan or add services.