Help with Design Team Dynamic Problems

We are a small team of UX/UI designers in an organization.

Often we are micromanaged by a single designer who has direct links with highest authority. Instead of going in the usual route of identifying use-cases, design thinking, iteration with users, refinement after/with the development team, we often find ourselves constrained a high-profile person, with direct connections with the designer, who wants something "now" and a quick design ready for development.

Often our work is extensively expert reviewed by this designer for hours and we find ourselves spending a deal of time trying to satisfy what is wanted to a point where there becomes too little time to actually test our designs with users and developers. It often mentally drains you to a point where you simply don't feel like it really matters if put in more hard work. I presume it probably is because the credit will go to this designer, who is a person of authority–not you.

The problem we're facing is this designer has a doctorate in some area of experience design, has over 25+ years of experience and directly interacts with the highest authority of the organization.

I tried to escalate this problem but haven't succeeded completely. I need alternative perspectives on this so that I can raise awareness on how this is hurting our progress as a team.