Telegraf exec, json and Prometheus

Hello there, on my telegraf.conf I have an inputs.exec that runs a script (speed test for the internet connection).

commands = ["/usr/local/bin/speedtest-cli --json"]
timeout = “1m”
interval = “60m”
name_suffix = “_speedtest”
data_format = “json”

It is working (telegraf is running the script), and if I send the output to a file I get data like this, as expected.

However, on Prometheus I dont see any data (I do see the fields exec_speedtest_download for example, but not the data.)

Is there a way to send data (json) from a executed scritp directed to Prometheus?