These are the main points according to the article:

Disrupting “super apps” that encompass many different programs and could degrade “iOS stickiness” by making it easier for iPhone users to switch to competing devices

I’d imagine this is about setting standard apps for many different things (for example maps, music) and also allowing these apps the same levels of system access as the Apple apps have (for example allowing Google Maps to display full screen directions on the lock screen during navigation). Also the 30% fee for competing services like Spotify.

Blocking cloud-streaming apps for things like video games that would lower the need for more expensive hardware

This is about Apple blocking game streaming apps from the App Store.

Suppressing the quality of messaging between the iPhone and competing platforms like Android

This is obviously about iMessage and the blue/green bubble “issue”. This is irrelevant where I live as we simply use other messengers, but okay.

Limiting the functionality of third-party smartwatches with its iPhones and making it harder for Apple Watch users to switch from the iPhone due to compatibility issues

Essentially allowing access to more system functionality and integrations with non-Apple smartwatches.

Blocking third-party developers from creating competing digital wallets with tap-to-pay functionality for the iPhone

So the ability to bind the double-click to Apple Pay to other services.

If it’s all that “classic”, then why is there no dedicated server software available? Let people run their own servers like back then. Would’ve fixed the issue of only 3 being available at first.