What exactly is "matchmaker" relying to?

What is it from player stats the matchmaker is making its decision? I am asking because on some days after i play a nation for several days it starts putting me into teams where i am ranked 1 st to 5 th after a match that is lost. i become one of the best players even though i am medicore and still it keeps putting me into such teams. Teams that do not use the game mechanics like ping on map or call air when pointing in the direction to give azimuth. some spam air the whole match, some keep respawning and allways chose the direct route to death, not once but up to 3 times until they leave with zero points.

I mean come on, when i start a nation which i paused to play for weeks or even month i have always the same expirience: matches seems balanced and fair, i slowly raise my win/loss ration (not Kill/death ratio which some people cant differentiate, but even that gets sometimes better) until i reach a point somewhere above 50% and then its starts all the way going down like : no you cant have a higher win/loss ration so we put you now in less expirienced players team. It happens all the time! but f i play sweden or Japan it keeps the balance or even letting me getting higher than 55% but all other nations like Italy, USA or even germany i have the same patterns! Of course there are days where i have loosing streaks with japan or sweden aswell but it goes away after 10 or 15 matches. i am not saying that i only loose with the other nations but winning becomes harder after a few day.

So my assumption is that each time i re-start a nation after weeks the game is collecting outcomes and measures the W/L ration. and when i managed to get a specific % of wins it starts putting me in weaker teams. I dont know how to explain it otherwise. I think the matchmaker is flawed.

If it would respectivly check players overall gametime; k/d ratio and foremost capture points it could determine the strenght of each individual. i shouldnt end up always in a team that doesnt even know how to teamplay. this is absolutly driving me mad and i absolutly frustrated by this.

Sometimes i even think its deciding on the actual daylie tasks like “wine 5 matches with an activity at least 50%” and then i exprieince gtetting stomped 15 times in a row…

so what are exactly the data the matchmaker is working with? where can i see an official gajin explanation