At first I was thinking… nah… the Hype Reflect app can go full screen…
Oh, it still has a black circle at the bottom right.
Then I was like… nah… Safari can go full screen…
Nope, it's like you say, the URL bar is still there.
So, if it was me making the presentation, I'd probably turn the project into an app with Xcode.
@MarkHunte has a project on GitHub could help.
Also, I made "Wrapping", which turns a Hype project into an app by "wrapping" it with a WKWebView.
There's a video here…