Player rating for tournaments across all installments of Heroes.

You consider a novice to be a player who has no tournament experience. I believe it's a new player who doesn't have a tournament rating. Moreover, they may have extensive experience gained on another platform...

Let's look at things realistically. In this year's tournaments, newcomers (Maximix doesn't count; he was already known as a leading player in 1v1 matches on another portal) can only showcase themselves in 5v5 matches because the game itself is new. And as the portal develops, the chances for newcomers to immediately stand out will decrease. The standard situation for a novice is: they come, they see, they are amazed (by the winner's result). Only the aforementioned Maximix has jumped in from another portal for a single tournament, and that's it. Therefore, it is reasonable to assume that if a person doesn't have a rating, they also don't have experience. Exceptions will be rare, and note that each such exception can only slightly influence a single tournament. Moreover, the number of newcomers will always be small.

I believe the formula ∑(Ri)+30*n(a) is quite optimal, as already mentioned.

As I already wrote, it's the same thing, just viewed from a different angle. If this makes it clearer, I'm all for it.

The calculation mechanism is unclear. From the formulas, it seems like (10*60+5*20)/1000=700/1000=0.7 or something else? Please provide an explanation of your calculations at least...

Of course, I calculated using the original formula:
(10*(60+20)+5*20)/1000=0.9

It won't be difficult to beat 50 or 100 newcomers (if they are truly newcomers in the sense you mean). It's much harder to beat 5 aces. I'm saying this based on my experience in tournament battles, not just pure theory. This means your coefficient is not tied to reality, which speaks against it.

It is very strongly tied to reality, specifically to how things happen on our portal. There are no friendly matches between top players here, and there are no tournaments specifically for newcomers. In a tournament, there are always strong, average, and weak players in the most ordinary proportions, and it's not even possible to gather all the strongest players in a given area. This year, for example, there were 3 tournaments in 3v3, and the compositions were very different. For example, out of the top 5 in the 3rd stage of the VK tournament, only vbn was present at Atamana's tournament. So, your examples are not realistic.

But it seems to me that by solving the problem of how to beat the top ten strongest opponents, we automatically solve the other two...

Again, no. If the places were always distributed according to the rating, then why hold tournaments? The rating is a measure of the probability of a strong performance.

But there is a nuance here. According to your proposal, the difficulty coefficient for playing against 10 aces (rating 100), for playing against 20 average players (rating 50), and for playing against 50 newcomers (R=20) is the same: k=1. Intuitively, this creates a contradiction... This is not a situation where quantity turns into quality... Because if you combine all the opponents together, in your case, the coefficient would be k=3, i.e., we see a linear dependence on the number of players.

As I already wrote, all tournaments have a very uneven composition of participants. And if the proportion between strong, average, and weak players was always the same, then the coefficient would indeed depend only on the number of participants, which is very logical. If the ratio changes, the coefficient changes.

But in practice, it is not very applicable due to the lack of an intuitively understandable explanation. It does not have a physical model as an example. It cannot be explained "on the fingers." And this is a minus in our case.

Here, you are definitely very wrong; there is a physical model, and it is taken from this portal. The model is as follows:
-tournaments involve players with very different skill levels
-there are certain proportions between the number of players of different levels (conditionally strong, average, and weak), which change from tournament to tournament
-the fluctuations of these proportions are not too large (at most, a few times, but not an order of magnitude)