Greetings 1pittpitt,
Thanks for visiting the Apple Support Communities! I understand you're having trouble using the Maps widget, as you're being prompted to enable Significant Locations when the setting is already turned on.
I suggest to remove the Maps widget from your iPhone, add the widget back to your device, and then test the behavior. You can see those steps in the following support article: Use widgets on your iPhone, iPad, and iPod touch - Apple Support
If the behavior persists, I suggest to delete Maps from your iPhone, download Maps from the App Store, and then test the behavior: Delete built-in Apple apps on your iOS 12 or later device or Apple Watch - Apple Support
Let me know how it goes from here.
Kind regards.