Here is something that may be helpfull for "correct" rankings system.

I'd like to see if anyone has a good model to estimane win chances for these cases.

1)
Assume we have 3 players A,B,C. All games are equal(we can not see the ally placement or sides)
player A played 2 matches with B and won 2 of them
player B played 3 matches with C and won 2 of them.

What is the chance of a win for A in a next game between A and B?
What is the chance of a win for A in a next game between A and C?

2)
Assume we have 4 players A,B,C,D. All games are equal
player A played 10 matches with B and won 1 of them
player B played 10 matches with C and won 1 of them.
player A played 2 matches with D and won 2 of them
player D played 2 matches with C and won 2 of them

What is the chance of a win for A in a next game between A and C?
What is the chance of a win for B in a next game between B and D?