I completely agree that not all participants will play in each stage. That's why there are 10 stages. Points will be awarded for each stage according to the scheme you proposed (it seems to me to be the most optimal for such tournaments). That is, we will get a picture where those who participate in a stage receive points, and after each stage, intermediate results are summed up. Those who did not participate in one of the stages have the opportunity to try to make up for it in the following stages. I think that each participant will play in at least 4-5 stages. And then we will summarize the results. It turns out to be something like a world biathlon (or skiing) championship. And we will have our own "Heroes" multi-event, thanks to which it will be possible to assess the strength of different players in different versions and the strength of players in all versions. A team can be formed from the winners, a portal team.
I will be glad to hear other suggestions.
And what will the results be??? The one who played the most games is the best player! This completely discredits any rating system. The rating should reflect the strength of the player, not the number of games!
But the main thing is, who will organize it. First of all, qualifications are important here. And not only of the player, but also of the judge!
And if a team is formed from the leaders of such a tournament, then I just have to leave here... :( :(