I'm not familiar with e-sports. It isn't popular where I live, but I know it is popular in some countries. In Korea, there are big buildings (like the basketball ones) where the crowd watch e-sports.
The competitions have big prizes and many people place bets. That means that the procedure must be transparent and the software behavior should be known. All competitor must have the same conditions.
First every competitor should use the same hardware specs. The first problem is that no CPUs are equal. Modern CPUs have a boost that increases the speed dynamically limited by the temperature, but two CPUs that are from the same product will have different limits. For that reason, the boost should be disabled.
The operating system should be the same image (including same packages and versions). Because Windows is closed-source, it lacks transparency and it isn't reliable to be used in a fair competition. For that reason, a Linux/Wine image is more reliable.
Finally, games... Old games developed before the popularity of e-sports are unlikely to have problems as long as the version is the same and the data is unmodified. But new games may have hidden cheats to help competitors that buy them. Hidden bugs may also lead to unfair help. Without the source code, it is difficult to detect the cheats.
E-sports games should avoid random functions. Even with a fair RNG, favorable results mean good luck rather than good skills.
