Lock down the Internet - but allow Google Maps and Navigation with in Google maps
Regarding the Navigate button access, it appears to be a default behavior of Google Maps, if you try accessing the Navigate button in maps through a web browser, it will ask you to open the Google Maps application instead. Probably, this could be the reason that you're not able to access Navigate button in SOTI surf.
As a workaround, I would suggest you to allow Google Maps (App) on the lock screen and blacklist all the browsers other than SOTI Surf and make SOTI surf browser as the default browser. And then in SOTI surf, you can whitelist only the sites you would want to access.
In your case, when user searches for 'Costa' and tries to access other sites using the link available in the maps application, all the websites are opening in the default browser and if your default browser is SOTI surf and you've whitelisted the content in SOTI surf, users wouldn't be able to open unwanted content.
Please try if that works for you.
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