Become the person deadlines are safer around.

Deadlines involving unreliable people require padding, chasing, and contingency plans. Deadlines involving reliable ones require none of that, which makes everything around them faster and calmer. Becoming that person changes what people are willing to attempt with you.

Start telling people the truth about timing, including when it is later than they want. A deadline that is accurate is worth more than one that is optimistic, and it makes you safe to plan around.