There is an easy solution, which may bring even more profit to MS: they should organize a live tournament with some $ rewards. Let us see how they play. There may be cheaters, but I never considered that, I was always too impressed by the possibility that there are some really good players and wanted to see how these brilliant minds look like, as an inspiration. And a cash rewarded public display of their skill may resolve all this.
There is a workaround for those who want to be objectively ranked among non-cheaters: there are 3 leaderboards, and one of them is "Friends". You only have to go to some social platform, make friends with like-minded people, non-cheaters, trust them and add them as friends. That scoreboard would give us a clue about best times for non-cheating players and about human limits. It may be a good idea to have people of your age in your Friends list.
But even the leaderboard as it is now gives me a decent estimation. In a group of 100 I always have to beware of those with more #1 places than me. At the end of the day, final group leaderboard is fairly reasonable.
Sometimes there is a bug. In May 2018 I have sent MSC a message via Facebook about finishing first game in 41 seconds, but leaderboard was showing 1:38. They resolved this and now it seems to be OK.
I am currently 11/7/11 (#1/2/3 place) and I also experienced an improvement of my skills. In the beginning I never thought #1 would be possible for me. Then I did it a couple of times. I have made my place in the upper part of the board and was stuck there for months. Recently I tried to be more focused and in last 10 events I had 2 third places, 3 second places and 2 first places, holding a first place in the current event, 8 hours before it ends. I am 55 and knowing how good teens are in gaming, I think it is quite possible that there are some young players who can solve everything in the half of my time. If we only saw one on Youtube, like that Chinese kid solving 3 Rubik cubes in the air, while juggling them...