Comment by Terretta
The full screen thing -- have you tried saving the SPA to the home screen?
Together with some meta tags, that launches full screen and stays full screen, like an app.
The bashing on apple for this "to sell more apps" is nonsense, Apple originally designed and intended for HTML5 apps to beat Flash.
One of the earliest games for iPhone was PacMac, it was a SPA web app saved to home screen, it worked great.*
OTOH, in 30 years of web dev, I never got pages about raccoons to work either.
* Haven't checked this lately to see if they deprecated this.
Home Screen Safari and Browser Safari act very differently.
There are a lot of bugs where home screen safari passes feature detection but in reality does not work.
iOS and Safari are hell.