WSL1 doesn't use a virtual machine, and only implements Linux syscalls as NT kernel syscalls. There's no VM or OS overhead; WSL1 is 100% userland software, except for the kernel translation stuff.

You should not have any issues with WSL1 in terms of system load or "weight" (whatever the hell that is supposed to mean in computer terms. This is used all the time and I've never once seen a definition for it. What is the unit of measurement? What's the border between "lightweight" and "not lightweight?" This industry as a whole ingests far too many hallucinogens. )