sorry to create a new thread, but the other one expired.
I ended up finding this modbus adaptor worked best:
I was attempting to connect to a wattnode and finally succeeded with a stable connection. Here is Wattnode: https://temcocontrols.com/shop/three-phase-power-meter/
and here is my flow:
Maybe someone else working with Modbus RTU or with Wattnode will find this helpful.