Scan location data is not accurate
You might have noticed that your scan location data only shows city and country and even then it's not always accurate.
The scan location is estimated based on the anonymised IP address of the device scanning the QR code. The estimate of the city and country is the best we can do with that.
If the person scanning the code is using a VPN (which masks their IP), their scan location might be totally off (e.g. they are in London, England, but the scan location is showing up as Wellington, New Zealand). Generally the location is roughly correct, or quite close. The location estimates are only there to give you a rough idea of where people are scanning your codes.
If you want to compare the performance of QR codes in different locations, your best bet is to create a QR code for each location and then compare which is getting more scans.
GPS location tracking
On the Business Plan and above you have the option to enable GPS tracking on your QR codes which lets you collect much more accurate location data. Learn more about that here