[walk|tread] a tightrope

to be in a situation where one has to be careful about every decision they make because even one mistake can pose a great risk

The idiom "walk a tightrope" draws its origin from the world of circus performance, where acrobats and tightrope walkers demonstrate their remarkable balance and skill by walking on a thin, elevated rope. Figuratively, it is often used to describe the delicate art of maintaining a balance between two opposing or challenging forces.

I’m walking a tightrope at the moment; one more mistake and I might lose my job.
As a diplomat, he had to tread a tightrope between the conflicting interests of two rival nations.
The CEO had to walk a tightrope when announcing layoffs, trying to maintain employee morale while addressing budget constraints.
In a complex legal case, the attorney had to tread a tightrope between defending the client vigorously and seeking a fair settlement.
Managing a diverse team can be like walking a tightrope, as the leader must balance different personalities and work styles.