I strongly agree with the OP.
In TOS, civilians and Federation civil authorities wore suits that were awkward but not atrocious. But starting with the movies, the civies got sensationally bad.
In TMP, McCoy beams up in a sleazy, "Hey baby, I have a hot tub" track suit with a plunging neckline. His giant gold medallion is just icing on the '70s schlock, and worst of all you can see more of the doctor's private practice than you want to.
In ST-III and IV, Kirk wears a lady's red pantsuit with a delicate lavender blouse that makes me want to puke. The backstory in IV says that they spent months on Vulcan before heading for Earth. So, having made such a horrible fashion mistake in III, why couldn't they get better clothes for IV? Vulcan is not a desert island.
In III, Chekov's civilian look starts out with a big, white collar that was so bad, when a studio executive saw it in the dailies he ordered it yanked. So it just disappears in the film.