Is there an OzzyBet app?
Not a dedicated native app at the time of writing — but the home-screen shortcut gets close.
There's currently no listing in the Apple App Store or Google Play for OzzyBet, which is common for operators in this category since app-store gambling policies vary by region and can require separate approval per market. The mobile browser site covers the same functionality instead — see the mobile page.
Home-screen shortcut, step by step
Open the site in your browser
Safari on iOS, Chrome on Android.Open the share/menu icon
Bottom bar on iOS, top-right on Android.Add to Home Screen
Confirm the name — it now launches full-screen like an app.