Give most of the space to the roles that best demonstrate your current level and consulting-relevant impact. Older jobs can often be compressed to company, title, dates, and one strong bullet or even no bullets if they are no longer material.

You still want the career progression to be understandable, so do not erase earlier experience completely if it explains how you reached the current role.

On a one-page resume, relevance and impact should determine space allocation more than equal treatment of every job. If useful, this guide on consulting experienced-hire criteria gives more detail.

older jobs get like one line on mine now.