To the best of my knowledge, no kernel level anticheat systems support Linux yet. So it's not something you have to worry about unless you're on windows.

Kernel anticheat is considered bad because it has full access to your computer. It's able to see everything happening on the computer to make sure you don't have cheats running. This is obviously bad for privacy reasons, and this is made worse because most games that use kernel anticheat are Chinese owned. The Chinese government is well known for spying on their citizens, and it's a very reasonable assumption that any kernel anticheat from a Chinese company is required to have backdoor access available to their government.

Other concerns are that it lowers the safety of computers. Kernel level access makes it very easy to compromise the computer. Genshin impact used to use kernel anticheat, but the anticheat was used to infect people with ransomware.

Furthermore, there's an ever increasing number of cheat options that don't run on the computer running the game, meaning that kernel anticheat can't even prevent cheating in games. An example is Aimbot software that uses a stream card to get screen info, and sends mouse inputs to instantly get headshots.