What assumptions? Go to your achievements, 300 ranked wins achi, and only 1550 rating. And you can’t lose rating until 1500. So you never hit 1700 rating in your 300 wins ( and at least 300 losses)
Do you lose on purpose or are you just that bad?
Then you need to get lucky to get a weapon, 4000 conquest is too much, 2500 would be upper limit for how long it should take to get a weapon, that’s 5 weeks.