Unlike your iPhone and WiFi & Cellular models of iPad, WiFi Only iPads do not have any GPS location capability with which to directly determine their location - and as such are completely reliant upon their network connection to infer an approximate location.
Without benefit of GPS, your approximate geographic location is inferred from a “database lookup” of (a) your WiFi Network Name (SSID) or detected neighbouring WiFi networks - and (b) the “public” IP Address provided by your Internet Service Provider (ISP).
If the mapped WiFi network name or IP Address are not available within the applicable databases, or if this information substantially differs between sources, then your approximate location may not be computed - or may wildly inaccurate. This situation often occurs if you are in a remote/rural location where neighbouring WiFi networks are scarce - or if connecting over satellite or VPN connections.
Network IP Addresses and WiFi networks are frequently mapped in urban and cosmopolitan areas (including “crowd source” techniques) and as such approximation of your location from lookup against these databases can be provide relatively high accuracy. As population and network density diminishes, this mechanism becomes progressively less reliable.
If you need GPS - and are unwilling to swap your WiFi Only iPad for WiFi+Cellular model - you can add an external GPS receiver to your WiFi Only iPad. These are often used in marine, aviation and vehicular applications - and can be either directly connected via Lightning or via Bluetooth. Their are various third-party manufacturers, of which one is BadElf.