Possibility to hide the Navbar for App

Hey,
I am working on transferring a non wordpress website to wordpress and have come across a problem that I thought would be simple but turned out it’s not.
The website has an android app which per webview displays the web pages. These are served from an app.domain.com subdomain which doesn’t show the navbar and adsense ads.
I figured I would handle it the same way on wordpress but it seems to be quite tricky to have a subdomain that serves the exact same content as the main domain and just does not display certain elements. The problem is that there can be absolutely no link which point to the main domain as the navbar would be displayed and ruin the layout and more importantly the adsense ads will show violating Google terms as the app is monetized with admob.
Sadly I can not just hide the elements on mobile neither as they are required on the normal mobile website.
If anybody could help me out with this it would be awesome!
I am also open to another solution without the subdomain if there is one.
Thank you!