I know, I said "I can imagine that my freetime will be even less the moment I start working.
" as well. I also spend at least 30 minutes doing my homework or studying for exams every day for 1-2 hours. So let's say 6 hours of freetime
Why would they need to understand? Just tell them that it's needed to play on the server and set it up for them. Whenever they want to play, they can use the VPN.
Have fun. As I got older, I deeply regret not going out or doing fun activities now that I am in high school. I had so much fucking time, but I wasted them all on stupid bullshit. Now I have only like 7 hours of freetime, and I can imagine that my freetime will be even less the moment I start working.
You should isolate it. Use Docker or Podman or any container solution to put the server in a container for isolation from the main system.
Any external directory outside the container the server won't write to should be in read only mode.
If the server is only for your friends. Stop exposing your network to the public and instead use VPNs.
Ridiculous? Bro, have you watched any anime?