After going back and forth with Oracle Support on this problem without any assistance from them, I worked more closely with my networking team to see if they could identify the issue. I was able to run my script on a virtual machine my team uses for development, but couldn't get the script to work on my own work computer, so we started there with troubleshooting to see if we could find a difference.

The solution that finally enabled me to stop getting the error above was to have the networking team bypass ZScaler SSL decryption for the OCI API URL, database.us-sanjose-1.oraclecloud.com. (I found that URL from my full error message while debugging.)