Apples to Oranges.
In 1776 there were 2.5 million people living in the U.S., most of which were given land and or jobs because they were pioneers and the declaration of Independence, The Bill of Rights and the Constitution granted them far more freedoms and rights than they had under the British. (Hence the reason they revolted from the British to begin with)
In 2023 there are 330 million people living in the U.S. As American societies grew in both population, technology, and business, certain regulations increased. Why? Well, having little to no regulation when a country only has 2.5 million people, little business, very little technology, industry, etc(1776) is vastly different than having little (or no) regulation when a country has 330 million people, with the largest economy the world has ever seen. Then add the amount of international terrorism, cyber terrorism, international and domestic criminal syndicates, vast international and domestic businesses, etc - yes, we need more regulation now than we did in 1776.
The current population of the UK is around 55 million people. Would you state that the UK currently has more freedoms than the U.S.? That is an Apples to Apples comparison.
As far as being "far more divided" than the Union was prior to the Civil War - well, if you're among the furthest 10-15% on either side, I would tend to agree. And social media and modern day technology add a tremendous amount of fuel to the fire, giving the optics that we are much more divided than we truly are.
If you're among the 70% of folks that are in the middle, people get along much better than the 15% of the far right and other 15% on the far left. But since the extremes tend to "scream the loudest" and most social media, cable news, etc is ratings and "clicks" driven, most of what we see and hear on a daily basis is the more extreme viewpoints.
Unfortunately, these views tend to drive further discord, even among some of the 70% that are in the middle because that's mostly what they see and hear as well. But if you were to actually sit down and discuss politics, social issues, etc with most people in the middle (with the absence of media and social media) you would likely find that most people's ideologies and viewpoints are moderate. And even on issues that they do not agree on, most in the middle (at the very least) try to understand and respect each other's views.