I figured it out. I can connect to the server via MySQL Workbench.
Something has definitely changed with the ports between the two version of TrueNAS. Under network configuration, leave Host Network unchecked, and add the port with Container Port and Host Port matching. Prior to the upgrade, this port mapping was in another area, and it gave me a message that I couldn’t use anything less than 9000 for the port - and even then, I couldn’t connect to the custom port.