Pulling in data from Teltonika router (RUT-X50)

Hi - I’m a complete novice when it comes to Home Assistant / home automation in general.

I have a Teltonika router that I’m trying to pull some data in from and I’m really struggling with it.

My first attempt was just using MQTT but that failed and I’ve achieved some partial success by setting up a MODBUS TCP Client/Server and then using the Data to Server on the Teltonika.

Using MQTT Explorer I can see the topics being successfully published and the values are as expected, however I’m completely failing to create sensors in HA that pick that data up.

I’ve done a search on here already, but unfortunately the only ‘solution’ I found was this one:

The issue being that opkg has been removed from the Teltonika RUT-OS so I can’t follow that.

Any pointers VERY gratefully accepted as I really have tried to figure this out and I feel like I’m tantalisingly close but failing at the last hurdle.