Good, unless you want to use an Apple Pencil
Scammer Developer
Well, to the developer, you are royally screwed. You have just violated the Equality Act 2010 law in the UK and the consequences will follow shortly.
You have to be lacking basic understanding showing that fraudulent message when the Obsidian vault is to be “kept downloaded” and never offloaded from the device by iCloud.
Regardless of how quickly you fix this, I am still going to put the screws into you and will drag you to court just to teach you a lesson.
Edit: it has been a while and the developer is still ignoring and insisting. For a developer you have to pretty dumb to insist files that are kept offline at all times “need” time to sync.