You can enable a feature in Cloudflare which will inject the approximate user's lat/lng (based on their IP (and other factors?)) as an HTTP header added to the original request:
"This Managed Transform adds HTTP request headers with location information for the visitor's IP address, such as city, country, continent, longitude, and latitude."
https://developers.cloudflare.com/network/ip-geolocation/
"This Managed Transform adds HTTP request headers with location information for the visitor's IP address, such as city, country, continent, longitude, and latitude."