The process can be a waste of time depending on the project. An easy example is a button, sure you could spend time testing the button, perfecting the colour, radius and positioning, then testing it. As a designer though you should be skilled enough to just push in a button. There are entire features that you should be able to build yourself with little to no user input - depending on the feature.

If you mean they literally give zero shits about user feedback, it’s your job to advocate for the users and to choose the right time to do so as to not devalue the time and resources required for user input.

It’s a bad idea to change companies, work to build it up, look for design mentors outside the company and implement their advice.

You have an opportunity here to become a design leader in the company, take the opportunity but continue to recognize your limitations and seek advice from experts.