Rating system for online games in Heroes of Might and Magic IV.

Points are awarded from the bottom; if there are few players, the winners receive fewer points.

This is evident in the example.

If there were 4 people, the first-place winner would receive one point; if there were 18 people, they would receive 12 points.

There isn't a formula, of course, but one could be devised.

I also suggested determining the points based on the tournament's difficulty, just in case.

By the way, a certain group of players has already formed for each hero, so the number of participants will almost always be the same.

Added after 34 seconds
I just wanted to contribute and give you a little break.

It helps.

Added after 44 minutes

Although you are right in some ways. You could simply set limits for the coefficient with Gw-Gl. For example, if a player has already achieved a solid rating, the coefficient could be reduced, say from 10(Gw-Gl) to just (Gw-Gl). The same applies to those with a low rating.
Rating limits could be established, from which the coefficient between Gw-Gl would depend.

As I understand it, we're talking about rating decay.

It should be the same for everyone, or it will become impossible to catch up with the leader