Can't apple map in Cambodia

the normal maps is suppose to be supported iOS and iPadOS - Feature Availability - Apple

but not the Navigation stuff

if you have problems with the nomral maps not being supported you can reach out to their support channels

Get Support (apple.com)

And or

Contact - Official Apple Support

And or

Contact - How to Contact Us - Apple

if you wish to urge them on to add more support then you can use their feedback channels

Product Feedback - Apple

Choose a feature in the link below to see if it's supported in your region. Maps. Standard; Satellite; Directions; Turn-by-Turn Navigation etc...

iOS and iPadOS - Feature Availability - Apple