The practical problem with the boiled down stoic approach is that in modern life almost nothing falls firmly and clearly into one of those two categories.
In OPs situation for example, webpack problems aren't under their control. But whether they use webpack, to some possibly very small extent, is. So now OP has the choice of whether to _consider_ it under their control, and push for a different tool that might make life easier. That may or may not be a good or satisfying use of time and energy, and OP is on their own for that, the stoic "control vs not" dichotomy has not been useful here.
This applies to like, basically everything that could cause someone mental anguish these days. Foreign wars, economic inequality, accessible biking infrastructure. These are all problems for me. All of them are outside my individual control, yet I still have a degree of influence to affect them.
Under this simple stoic approach, which bucket do I put them in? Assuming responsibility for every event I have any power to influence seems like a path to despair. But abdicating responsibility for things I feel powerless to change is also grim.
Maybe it has always been like this. And yes I am read up on the stoics and know that they have a lot more to offer for these calculations. I'm merely pointing out that giving people the simple "control/not control" technique is rarely very helpful.