Maybe this will save somebody some time pulling their hair out!
In the PLC, add an always-on ST1 and a PUBLISH instruction. Fill out the source register/bit you want to pull, MH for holding, and MHR for float. Number of elements, for real, I think it's 100, and option gives you different format options.
Add your Modbus TCP driver to your devices and open the addresses window.
Enter a meaningful prefix, starting register and ending register for tag creation, if values are float check the step option. Modbus Unit ID will be zero if you only have one processor, if you have more, you'll need to set unique IDs for each of them. Select the type of register and the starting position. When you import the tags to your project, they will have a HRF appended instead of the MHR designated in the PUBLISH instruction.
Bottom line is it works without using MQTT