Just thought I could share this simple trick to make any Bela GUI work as a fullscreen iOS app.
You just need to add these lines to the head of ~/Bela/IDE/public/gui/index.html
<link rel="icon" href="bela.png">
<link rel="apple-touch-icon" href="bela.png">
<meta name="apple-mobile-web-app-title" content="Bela GUI">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent">
'bela.png' refers to an icon I made using the bela logo, placed on the same folder as the index.html file. You can delete these two lines if you don't want the app to have an icon. Optionally, you can also change the viewport line to disable user-scaling of the interface:
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
If your bela is on a local wi-fi network, you just need to head to bela.local/gui/ on Safari on iOS and add it to the main screen. Voilà: any bela GUI will now be a fullscreen iOS app!