Welcome to the forum.
I do not think you can accomplish this purely in Grafana. I believe you will have to create a query in Influx that basically does what you wrote. That would calculate a new field in Influx, but it would not be a time-series based value anymore, right? You could then display this amount in Grafana in a table or bar graph or something that is not time-series based.
Another idea would be to use a Gantt chart that does show the start time and end time of each job, and then somehow find a way to include in each “brick” the energy usage. I have no idea if / how that could be done, but then you’d definitely be able to “see” the orders on a time graph.