In my experience HTTP is as if not more complicated than using MQTT. It’s less flexible too because it has to poll instead of having the new data published directly. It can work with HTTP for sure, but MQTT would in fact be the simpler solution, expecially given the JSON that you get from the HTTP polling request.
ESP Home even supports the Home Assistant MQTT standard so OH could just discover the devices and create the Things automatically meaning you don’t have to configure anything at all on the OH Things side.
There is also an ESP Home binding on the marketplace you could use: ESPHome binding for the Native API [4.0.0;5.0.0)
A JSONPATH transform won’t work here I think becuase the JSON uses a lot of arrays. So you might need to use a JS transform script to parse the raw JSON into a JS Object. Then you should be able to navigate and filter down to the record for “kominek2”. It’s a complicated JSON so I can’t say for sure if this is correct but it illistrates the approach:
JSON.parse(input).sensors.find(s => s.TaskName == "kominek2").TaskValues[0].Value
But you’ll be much better off using the add-on or MQTT in the long run.