I’d start with the main switch at Settings > Privacy & Security > Location Services and turn Location Services back on. Apple still lists that as the control for location access in iOS 27. → Control the location information you share on iPhone – Apple Support
After that, scroll through the same page and check Maps and any other apps you use, since their individual permissions may need to be allowed again.
If the Location Services switch is grayed out and you can’t change it, check Settings > Screen Time > Content & Privacy Restrictions > Location Services. Screen Time can lock changes to that setting. → Set up parental controls to manage your child's iPhone or iPad - Apple Support
I wouldn’t reset Location & Privacy unless those checks fail, because doing that clears the existing permission choices for all apps.