They've convinced Democratic political leadership that they must fight Trump wholeheartedly, and convinced most of the country that Trump is a bad president who's failing to effectively address any problems. More change will be possible after the next election, when Trump's severe unpopularity causes the Trumpists lose control of Congress.
Democratic political leadership were fighting Trump 10 years ago long before No Kings.
I don't think they have done much real, if anything.
This is hopelessly naive. The only thing that has changed people's opinions, is their own personal bottom line. No more, no less.