It doesn’t have to be 100%. The point is to make it inconvenient. The majority of people will not do it if it is inconvenient.

Thats the point to many things in life that you just make it more difficult and most people won’t be bothered to attempt to circumvent whatever it is.

There will still be circumventers but it is will be less than if you just said fuck it.

Correct. E.g. you can aimbot by routing the video signal to a capture card on a separate computer and run image recognition software to generate mouse movements spoofed at the hardware level. The only way to reliably prevent cheating is with in-person tournaments played on hardware provided by the organizers.

The best way is to just make private servers, so people can play with their friends and not have to worry about random players. This also solves the issue of people using.... language thats not acceptable in games.