[pull] {one's} punches

to deliberately hold back or lessen the force or impact of one's actions, often to avoid causing harm or offense

The idiom "pull one's punches" originates from boxing, where "pulling punches" means to throw a punch with less force or intensity than one could. In a broader sense, the phrase is used to describe the act of not putting one's full effort into something, often to be less critical or less forceful when expressing opinions, criticism, or feedback.

In the world we live in, you don't get anywhere by pulling your punches.
During the presentation, he didn't pull his punches and gave a straightforward critique of the project's flaws.
She decided not to pull her punches when discussing the issues with her co-worker's performance to ensure improvement.
It's not always easy to pull your punches in a debate, especially when you feel passionately about a topic.
He tried not to pull his punches when offering advice to the aspiring writers, aiming to help them improve their work.