Maps not loading; only showing grid.

I have noticed for a while now that the Maps app on my MacBook Pro no longer shows the map (streets, labels etc.) - it only shows grid lines. My current location is shown on the grid, and searching for destinations/directions and such works - a pin is placed in the correct position relative to my current location, and directions (routes) are shown correctly as if the streets were there - but over the unloaded map grid. Choosing 'Satellite' rather than 'Map' or 'Public Transport' shows the satellite imagery, but with no streets, labels etc.

This is also seen in other Mac apps-

• Calendar - previewing an events with a location shows a pin on the unloaded map grid;
• Find My - shows People and Devices in correct relative positions to each other and my current location, but on the unloaded map grid.

Things I have tried (none fixed the issue)-

• Starting the Mac in Safe Mode - only shows black where the map/grid should be in the Maps app;
• The steps in this thread: apple maps doesn't loading on mac - Apple Community;
• The steps in this thread: Apple Maps shows empty grid: solved! - Apple Community.

Any assistance would be appreciated - thanks!