I want to send alerts from Grafana to the HMI machines which are not support any internet connection

We want to send alerts from Grafana(Ordinary Grafana not the Enterprise or Cloud one) to the HMI machines which are not support any internet connection or even Ethernet; and they use MQTT channel.
For this issue in summary I found these steps:
1- sending an alarm from grafana using MQTT plugin in order to easily handle it in the HMI:
that could be the best one but MQTT plugin doesn’t support Alerting! And after reviewing all aspects, it won’t possible.

2- using webhook and MQTT broaker:
This one also can cover Rest API but for translating HTTP request to MQTT we have to use Node-Red (or if there is any other way) as a solution so it may takes some time to figure out.

3- sending alert to Prometheus Database
4- using Infinity, Json or HTTP Plugins
beyond these 3 plugins just Infinity is supported by Grafana Alerting but the point is we have to use .json file and our alerts are .yaml, so we have to find a mechanism to convert it.

I really appreciate if someone have a contact with me about that.