It is very clear legally speaking. There is a clause specifically to address this issue in the constitution called the supremacy clause. The way that it works is that if there is a federal law that specifies something then it takes priority over state laws. Some of the things that you mentioned would fall into both federal and state categories like education where states have some control but must also abide by federal regulations.
The only exception to this rule is cannabis and the only reason that it has worked this way is because cannabis reform is so widely popular across the US that if the federal government were to withhold funding or otherwise punish states for making and enforcing laws that go against the supremacy clause it would not go over well for the politicians that make that decision. They know that federal cannabis regulations truly are outdated and not in touch with our modern society. That being said, supremacy clause is still in effect and the federal cannabis laws are still absolutely enforceable even in states where cannabis is “legal”. The federal government simply chooses not to enforce those laws there most of the time.
Child labor laws absolutely do not fall into that same category as the vast majority of people don’t believe that child labor laws are outdated. The waters are not muddy on this issue at all.