Help a beginner: Why is my 'What is my City Name' tool's IP address lookup often wrong?

Hello everyone! I recently launched a simple web tool called 'What is my City Name', which, as the name suggests, aims to tell users their current city based on their IP address. I'm quite new to this whole space of web development and particularly to working with IP geolocation, so please accept my apologies if this comes across as a very basic question! My main problem is that users, and even I during testing, are consistently reporting inconsistent and often inaccurate city names. Sometimes the tool shows a city that is quite far from their actual physical location, which is really starting to impact user trust in the tool's reliability for an accurate IP address lookup. To try and tackle this, I've already taken a few steps. Initially, I integrated a couple of popular free IP geolocation APIs, specifically ip-api.com and ipwhois.io, hoping they would provide decent accuracy. I also implemented some basic caching for frequent requests, primarily to reduce the number of API calls and hopefully speed up the response times. I’ve thoroughly checked my server logs to ensure that the correct IP addresses are actually being captured and sent to these APIs for processing. Furthermore, I’ve conducted extensive testing myself, using various VPN locations and different mobile networks, and the inconsistency in the IP address lookup accuracy is definitely persistent across all these scenarios. I've made a few observations regarding the specific issues. A very common problem is that the tool frequently shows the location of the internet service provider's data center instead of the user's actual, precise city. Mobile IPs seem to be particularly problematic; for these, the tool often returns a very broad region or even just the country, rather than a specific city, which isn't very helpful for a 'What is my City Name' tool. The overall accuracy also appears to vary wildly depending on the user's specific internet service provider, which is something I hadn't quite anticipated. So, I'm really hoping to get some advice from the more experienced members here. Are there specific, more reliable (perhaps even paid) IP address lookup services or databases that offer significantly better accuracy, especially for city-level data, that you could recommend? Also, I'm wondering what common pitfalls or server configurations I might be missing. For example, could it be related to how I'm handling proxy headers, or perhaps issues with IPv6 detection, or even specific server-side settings that could be affecting the accuracy of the detected IP address? Finally, are there any general best practices for handling mobile IPs or any overall tips for significantly improving geolocation accuracy for a simple tool like 'What is my City Name'? Any insights or guidance would be incredibly helpful in making my tool more useful and trustworthy. Thanks in advance!