That is scripting.
Are we playing a campaign or renacting the Lord of the Rings?
Live for the chaos and mayhem. Expect it. Thrive from it. And tell the players that if their precious avatar dies, it’s on them, exclusively.
A campaign should be built around goals, capable of being moved around, delayed or put ahead of schedule as needed.
The players are walking in the campaign blind. It’s not their concern if a random action - that may be completely in line with their character - ampers, deviates or collapses the entire campaign.
Congratulations. Having high level characters and well rounded players does make everything smoother. If you’ve had those, I envy you. But not much.
I’ve managed a couple of games but I always made my plots to willfully accomodate chaos. I like to reward stupidity and recklessness. After a couple of disastrous events, the table tends to settle down and the mood tends to loosen up.
I’m fairly comfortable saying we have different approaches to playing and play directing. Which is good.