Depends on whether or not you want to kill only the child processes of a parent process or if you want to kill the parent as well. To kill the parent and children, you can kill the entire process group, specifying the pgid in the kill command. To kill only the parent you can trap SIGTERM in the parent and then send SIGTERM to the process group.
As someone who has done a lot of distro hopping in the past, I’ve found that going for a stable release that is widely used as a daily driver is superior for gaming than “gaming specific” linux distros, largely on the basis that the gaming distros have routinely had buggy UIs, driver issues, and a variety of unexpected and undesired behavioral problems tied to the array of “gaming adjacent” software installed, most of which you can install yourself with little to no effort and most of which you probably don’t want or need in the first place.