Currently, a state’s laws overrule the laws of cities and counties contained within it. What would happen if this were changed?

I’m not a lawyer. Having said that, I envision an amendment to a state constitution that looks like the below:

Unless deemed as harmful to residents of neighboring areas, all state laws may be superseded by local ordinances and laws. This amendment shall not be construed to overrule federal law. Direct harm to a group of people or individual must be shown to overrule any municipal or county law. This amendment also does not preclude laws that may directly harm individuals, such as those of a bill of attainder.

With this law and more thought of edge cases, many problems would go away.

This would enable a county to set its own laws when it disagrees with the state. For instance, if the state makes owning a rifle require licenses and permits, a county could create its own law that overrules that state law while the state law is challenged in court.

Other examples may include a county that wishes to make abortion illegal in the case of Roe v Wade being overturned at a federal level.

This also applies to laws such as HB2, where the state could not tell cities that they cannot set their own minimum wage or create their own anti-discrimination ordinance. Counties or cities not wishing to set their own regulations here could allow state law to be in effect.

This makes it so that there could be a large number of different laws. There would be more borders where when you cross them you are entering a different area with different rules. How would this play out in practice? I think it would have problems. Are those problems worth it? We could make it so that some of the most contentious arguments have a lower impact on communities.