A 'plot' is just stuff that happens to nudge your protagonist along their arc.
Anything can happen, but what needs to happen? Plot is like the tourist traps you can visit on a road trip: they are 'there' whether your protagonist stops to take a picture or keeps on driving. So which is better, the northern route or the southern route? Both have sights to see. Both have food and lodging. Both eventually reach the same destination.
The protagonist's character arc, how the character changes, is the actual story. The plot needs to facilitate those changes. Robert McKee's lecture on story says that every scene must 'turn'. That means each scene needs to have an impact on your protagonist's state. Scenes don't follow the protag driving straight-ahead down an endless highway. Scenes need to show each 'course adjustment' the character makes internally. In the structure of a tragedy or horror, we see the protagonist reject opportunities where they should have course-corrected.
We all know screenplay formula tropes where the MC has to face a certain psychological flaw in their behavior – which is weirdly specific to the situation they are in – before they can 'succeed'. But even so-called unchanging protagonists experience an internal arc. A detective has several state changes as they pursue a mystery: they are unsure or reluctant, they analyze the facts and become skeptical, which leads to a flash of insight about the crime, and eventually they have a suspect but need to trap him. All of these are internal state changes. 'Character-driven' doesn't mean the protag is reliving childhood trauma in every scene, but they are still motivated by an internal state which changes as the plot progresses.
To go back to the road trip metaphor, plot is the towns and scenery along the highway but the actual story is about this inner journey: the decisions the driver must make to correct their course, whether they believe they can make it to the next gas station, why they decide to stop for the night or keep going. Those roadside attractions are interchangeable, but the character's internal state is always specific (even if their internal state is discovering they are lost).
How to choose between two paths
Separate the protagonist from the author. The protagonist will act out of their habits and experience. They will always choose the path of least resistance, the easier road – until they have a strong motivation to choose differently. This doesn't mean they are making the 'right' choices (we all know people who habitually make bad decisions).
As author, you have to design a highway that thwarts the protagonist's easy journey. They want to take a shortcut, but it leads to unexpected consequences. They try to take the safe route, or the one that's familiar, but as author, you need to wash out the bridge, knock a tree across the road, and close the last gas station. These are plot events that force your MC to change course.
If the protagonist knows the bridge is gone, or a tree blocks the road, they aren't going to travel that route. Healthy people avoid problems unless they have a strong motive to confront (or cause) them. Conflict (always a good thing in a story) is when your protagonist stumbles into danger, or unwittingly picks the wrong path. Conflict forces your MC to do the thing they didn't want to do: take the less easy road instead.
As author, your job isn't to offer a series of scenic tourist traps along a highway. Your job is to show us why the protagonist decides to take the northern or southern road. Let the reader in on this decision process so they understand why the protag has chosen their route. Then, as author, your job is to thwart their journey in each scene. Force them to make small sacrifices and ignore the warning signs to stick to their original plan – raising the stakes as we approach their breaking point, until ultimately the bridge is washed out ahead, a tree blocks the road back, and they've run out of gas.
The plot you choose should be the path that looks easiest to your protagonist, but is (ironically) also the path with the most conflict they are not prepared for.