What you are describing doesn’t match with my understanding. As I understand it, if anyone buys at your location, you collect state, county, and city tax for your county. If you ship to someone outside of your county, then you typically collect state AND local taxes related to that destination city/county. We sell into over 30 states and I’ve yet to see where they allow collecting only state tax. An exception might be if you are registered through Streamlined Sales Tax . Then you may collect at a fixed rate but that is still determined by that state.
I’d look destination vs origination tax requirements. Be aware too that some states require sales tax on shipping.