The US federal government does have some oversight and regulation of schools (largely through funding programs such as the school lunch program - fun fact, only exists nationwide because of the high rates of malnutrition for WWII draftees), but because states contribute the overwhelming majority of funding through property taxes, they tend to have most of the sway on what happens within.

The role of the federal government in education (on paper) is to step in when students’ rights are being violated in things such as discrimination (most notable during the desegregation and activist movements during the 60s/70s), but a lot of those protections are being dismantled by the first, and now second, Trump administration (largely by de-fanging the Department of Education).

This caused states to start implementing their own standards and working together to try and push back against societal backsliding and censorship/erasure (using my home state of California again as an example, having robust LGBTQ+ protections in curriculums and safety, alongside active aid programs for students in need). While I don’t think there is an active “cross-state standard” for graduation and employment, some organizations outside of government do have standards that employers rely on (such as certifications). The emergence of the “Pacifica” bloc of states to try and collaborate on legislation and reform (California, Oregon, Washington state), may be the first of its kind towards what you’re describing.

Edit: typo fixes

Edit Edit: Also, private universities in the US (along with prestigious state colleges like MIT, California Polytechnic(s), and Texas A&M) are usually held on a pedestal compared to normal college graduates (although college graduates from any school are more preferred over High School diplomas) usually because of their very rigorous academic requirements to get in compared to standard colleges, since money alone won’t carry you to graduation (you WILL get kicked out if you aren’t learning anything).