Remotely lock my son’s computer from within the home network and possibly my phone

I am trying to find a way to remotely lock my son’s computer to prevent my daughter from sneaking in at night and getting on the internet and playing his games. I have our computers (both running Windows 11) setup to share certain files and folders and figured I could create a shortcut on my computer to a .bat on his computer to be ran to lock his computer for when he forgets to sign out due to being in the middle of a mission in a game and cant save and he forgets to switch users. I am aware of the auto lock setting in the screen saver control panel applet but it just isn’t quite what I need.

I have tried to do this with the batch file (as mentioned above) using the rundll32.exe user32.dll,LockWorkStation command but it just locks my computer, plus I just read on here how that command can damage a computer.

So, what are my options? Do I need to run windows server? Is there a way of taking ownership of his Windows folder and giving me access to run the aforementioned command or another command? Would you recommend any 3rd party software? Freeware preferred, paid software is fine as well. I just to get a handle on this and not leave my daughter’s protection from the internet to chance (since she is so sneaky, I need to add more control and layers of protection). Also, I am aware of and using the Microsoft Family app/feature, but it is not enough, I cannot schedule when he is allowed to use the internet, only how long he can use it and it doesn’t stop apps with chat features either. I am taking advantage of all the family features I have at my disposal, but this is the last piece that I need. Thank you all in advance. It ain’t easy being a parent 😬

ADDED INFO: If there is a way of doing this via cmd, I will be adding it to task scheduler, creating a hotkey using AHK, creating a shortcut on my Elgato Stream Deck and my HTPC universal remote. I want to have as many ways of executing this as possible. None of these I need help with, I am just letting y’all know how I will be using it once it is figured out. Thanks in advance!