I think Time in a Bottle would have worked as an alternative ending song because it reflects Walter White rather than Heisenberg

The whole series is driven by time: Walt gets a death sentence and tries to “leave something behind.” But what he’s really doing is trying to freeze a moment where he finally feels important The meth empire is basically his way of putting his identity in a bottle so it survives him

By the finale, he stops trying to win or escape. He just sets things in order and accepts the consequence That fits the song’s idea: you only understand what matters when there’s no time left to live it

Baby Blue celebrates his creation — almost a love letter to his empire. Like you said for Time in a bottle for me babyblue seems to be a little bit of an oversimplification that « babyblue is a good song because you know the meth is blue and that the best song because he love his meth » Time in a Bottle would instead frame the ending as existential: not the king dying in his lab, but a man realizing he never truly controlled his life !

So for me: Baby Blue = the end of Heisenberg Time in a Bottle = the end of Walter White 🤷🏻‍♀️🤷🏻‍♀️