Not really. As far as I’m aware there’s nothing in law that differentiates between selling a product and providing a service. However the whole problem here is that the law isn’t actually that well fleshed out.

The 14th Amendment gives equal protection under law. This basically says the state can’t treat any citizen different for any reason. Thus, a court can’t refuse to hear your case because you’re black, and a state can’t refuse your marriage because you’re gay. This only really applies to governments, however.

The Civil Rights Act has various Titles, most of them still relate to the state (eg voting). There are two exceptions where this goes beyond the public sector, though, Title VII on employment and Title II on inter-state commerce. Title II outlaws discrimination based on race, color, religion, or national origin - but not sex nor sexual orientation, and it only applies to inter-state commerce. Title VII prohibits private employers from discriminating against employees on the basis of race, color, religion, sex, or national origin, but might not cover sexual orientation (I haven’t found a definition on what “sex” covers, orientation might fall under this but it might not).

There is other legislation covering specific aspects, such as the Americans with Disabilities Act which provides extensive protection to people with disabilities.

Beyond that, it is up to individual states to set their laws. However, they must do so within the bounds of the Constitution, which is what allows free speech challenges like the one in the Supreme Court ruling over 303 Creative v. Elenis, which set a clear precedent allowing private businesses to discriminate regardless of state law.

All in all, anti-discrimination laws in the US are actually very weak.

IANAL, feel free to correct me if you know better.