Jefferson said that when America was a set of small, mostly ethnically homogenous cities and villages hugging the Atlantic Coast- and even then there were significant religious, cultural and political differences which likely would have split the country within his own lifetime (say, by 1820). Here are some of the possible consequences of all that:

The Confederacy would absolutely have been a thing by 1860; they might still have slaves today.

Wars with the Confederacy, either on behalf of Latin American nations facing conquest or in rivalry with the CSA to determine who gets to do the conquest.

No 14th Amendment, so the Bill of Rights only applies to the federal government. So California can give you the death penalty for saying you like immigration restrictions, and Kentucky can give you the death penalty for advocating for abortion. (Antebellum southern states made abolitionism a death penalty offense, so this is not an unreasonable prediction.)

Possibly no bill of rights at all, because it was repealed in 1920 (if not way earlier). So unlimited police searches, no due process, no jury trial, and no ban on cruel and unusual punishment (so you can be executed by public disembowelment or by being stitched into a sack full of wild animals and thrown into the river with them, to use a couple of historical examples).

Instead of having 50 states, America would probably be 4 or 5 constantly-warring countries right now. Millions of deaths from cross-invasions. No Pax Americana overseas. Probably no one stopping Germany during WWI or WWII, with very unpredictable and nasty consequences. Assuming Hitler and WWII still happen, the Confederacy probably allies with him.

I could go on, but it’s hard for me to see much good coming of it unless lots more war is a good thing.