I am teaching how to code Python at a high school and I wanted to know if there's some software I could use to control what the students are doing in real time. I only want to watch their screens in real time, I don't need to interact with them or something more. I would need a free software, because we don't have a budget for this.
You should checkout Veyon.
It's open source, available for both Windows and Linux, it does more than you need but those extra features are handy and won't cost you anything.