Hi there
I have build something almost near to this that was for tracking employees and it has chat and map features.
we are a group of experienced developers in Android, iOS, and Swift and VIPER architecture. We have enough skills in Flutter and React native for mobile. With hybrid languages like Flutter or React Native, you can have one code for both platforms iOS and android.
Please contact me over chat to talk about your project in detail and let me see your UI designs if you have it and then I can give you more exact price and time.
Also, we will support the app for 6 months so don't worry about future bugs.
Hope to hear from you soon.
Thanks