I have an iPad myself and try to use it to work every now and then. I always run into pretty basic limitations on iPadOS very quickly. For example working with large file on a network share is painful. The file manage is a slow toy compared to the Finder. The limited RAM and no swap means app will lose state regularly. Transferring data between applications is still cumbersome.

they were constantly talking about the push to unify macOS and iOS UI

They made several attempts at it and none succeeded. There's lots of shared frameworks, Mac Catalyst, and Swift UI. None of them work consistently or are particularly good.

iOS and iPadOS have fundamental limitations baked into the design that severely limit it.

Making a unified mobile, tablet, touch, and desktop OS was also tried by Microsoft and Ubuntu and the results were weak to mixed.

What Apple really needs is a new paradigm. For that they need a vision, which they don't have since Steve Jobs died.