A laptop is not a great controller for a bunch of reasons, mostly having to do with power management features you don’t want and high cost for portable but limited performance. Another option might be to buy a cheap, discreet, dedicated system you don’t hook up to the school network at all, such as a NUC - Amazon.com: Beelink EQI12 Mini PC with Intel 12th Gen Core i3-1220P (10C/12T,up to 4.4 GHz) | 16GB DDR4 500GB SSD Mini Desktop Computer | Dual 4K Display 2*HDMI | 1000M LAN WiFi 6 BT5.2 | Auto Power On : Electronics
Some people have also had good luck running a Windows 11 installation that has some of the bloatware already stripped from it, such as Windows 11 IoT Enterprise LTSC - see Windows 11 IoT Enterprise LTSC