you can't dismiss all possibility of skill being involved purely based on the fact that there are some random variables involved.
but videogames are inherently random, it's part of what makes them replayable.
There aren't "some" random variables in video games. Almost everything is random.
Let's look at CSGO.
Where you spawn is random. I know it doesn't sound like much, but a second or two can make a world of difference when it comes to getting to AWPing spots before the other team's shooter does.
Now weapon spreads. Sure, pro players will actually memorize how the weapons spread, but there's a random element to how they spread. Again, you can randomly kill somebody. Entire tournaments have been won because a guy heard a player on the other side of a wall, and hipfired an AWP, a one hit kill gun with a random hipfire spread, into that wall, and hit the dude and killed him. By random.
Also, the fact that these games use 64, or 128tic servers or whatever mean that some of the shots you make don't land. Glitches in games are just a part of playing them, like I personally have a huge thing with CSGO because on vanilla servers your shotguns will literally not register.
Like, you need random elements in a competitive video game so that it doesn't turn into a board game, and that there's suspense and excitement, but you can't have that in a professional setting.
Like, if they gave the AWP a crosshair and lazer accuracy it would be much less bullshitty because "oh, he aimed and killed me", but it'd ruin the game because everybody would use it, and it'd turn into insta-gib sim2000, kind of what Unreal Tournament competitions turn into, because the hitscan lazer guns are perfect because as a pro player you can rely 100% on your accuracy.