Welcome to the Losant Forums! I do believe Losant would accomplish your task, and all you might need is a way to get data to and from your Raspberry Pi(s). This can be done a multitude of ways, but I will include relevant Pi content below, which usually includes MQTT. You say “commands would be sent from PC or mobile device,” do you have a way of sending these commands now? Or would Losant’s Device Commands likely be your way of sending (and possibly receiving)?
Here is some education content for the Pi: