Hi,
I believe there might be some confusion regarding the concepts of locking and unlocking components, as well as how they function. To put it simply, locking a component means that it cannot be moved or removed; it can only be edited according to the policies defined by the template author. Unlocking components, on the other hand, means they are free to be moved or removed.
When dealing with the initial setup or your specific scenario, the best approach to achieve this situation is to lock components that don't require rearranging. If, for example, you need to allow some components to be inserted in between components that should not be moved, I would suggest adding an unlocked container component in the middle. This way, authors can freely place any other components between those mandatory components.
Please, read this thread which can help as well:
https://experienceleague.adobe.com/docs/experience-manager-65/developing/platform/templates/page-tem...
https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/editable-templates-locked-...
Esteban Bustamante