All cubes in each round are scrambled the exact same way (a computer generates a 40-move scramble that is scrambled by volunteers before the cubes are returned to the tables).
Scrambles are not 40 moves, they're generally around 25 because they're somewhat optimized scrambles to reach a randomly generated state. Simply using a sufficiently long sequence of moves still provides some bias to certain cube states, which is why they don't do that.
Me too. I used to cube in my teens. All my record solves were basically due to RNG, i.e. lucky scrambles. The average of 5 is a much more useful metric, if we’re looking at who is the fastest solver.
I’m just a beginner level cuber but my impression is that starting condition of the cubes is likely controlled for. It is common to share the set of moves used to ‘randomize’ the cube.