Yes, I have that set up. Unfortunately, Apple still wants to do things a little differently. Apple looks for a start up splash screen.

Here’s a forum talking a little about it.

https://forums.developer.apple.com/forums/thread/733490

And this is a generator:

https://progressier.com/pwa-icons-and-ios-splash-screen-generator

The key seems to be ensuring there is: apple-touch-startup-image link 

It sounds like it’s a pain because there has to be one image per device size… but, maybe UNA could pick the top three or four sizes and that could be good enough.

The experience now isn’t awful, it’s a blank screen as the site loads. But, it feels more like an app when you see the splash icon screen first.

Good old Apple/iOS insisting on doing things differently.

Examples:

My UNA site loading:

Another site of mine loading that uses a different CMS: