I totally get the frustration with that notification. It does feel annoying when you just want to use the app without sharing your location. The good news is there's a way to stop that notification from popping up.
Here's what you can do:
Go to Settings > Privacy & Security > Location Services. Scroll down to Reminders and tap on it. You'll see options for location access. If it's set to "Never", the notification appears because the app is checking but can't access location. Try setting it to "While Using the App" but then toggle off "Precise Location" at the bottom. This way the app has approximate location (which it needs for location-based reminders to work at all), but it won't track your exact position.
Alternatively, if you don't use location-based reminders at all, you can just turn off Location Services entirely for Reminders by selecting "Never". The notification might still appear briefly, but after a few dismissals it should stop bothering you.
Also check if you have any location-based reminders set up. Go to the Reminders app and look for any reminders with a location pin icon. If you have any, either remove the location or delete those reminders - that's often what triggers the notification in the first place.
Hope this helps you get Reminders working without the nagging!