Array Resistor Temperature Coefficient
That TCR of +/-200ppm/°C is not drift, it is the temperature coefficient.

Drift is the change in value over time. Example: after 1 year of continuous usage it is guaranteed to have deviated (changed its value) less than 1%.

Indeed it can be expected that the resistors in a single package array are "more similar" than random resistors from random batches will be. However, the datasheet does not state anything at all about this! So how much "more similar" you can expect the single package resistors to be is anyone's guess.

Also I interpret that TCR of +/-200ppm/°C as a maximum and it is. See it as this: Samsung guarantees that the TCR is within +/-200ppm/°C, that still means the TCR can be positive or negative. Only if the resistors have a TCR outside the +/-200ppm/°C limit would they assume "something went wrong" and they should then bin (throw away) these resistors (in practice, they might end up on Ebay). I mean: Samsung isn't trying to make the TCR equal to zero.

If you want/need better specified resistors then you need to look at the more expensive, more accurate types.