XB1 is likely over Switch, but not because "it was at 41m by the end of 2018 no way sales fallen that bad" (because to be honest yes they fallen REALLY bad), it's because we talk about shipments numbers.
Let's start with the fact that the 41m figure is an estimate and not an official number, but let's say it's true, that was sold through. Sell in numbers should add 1/2 million more, so it was likely 42/43m sold in. So even if XB1 literally sold 0 units in 2019, it would still be above Switch in term of sold in numbers. But this doen't matter that much, because before the end of this year Switch will 100% surpass it (sold in and sold through).