I wrote a 160,000 word book this year on an iPad Air with smart keyboard (I find how the pro keyboard doesn't fold all the way back to allow holding the iPad landscape too big of an annoyance to buy one). I think it's a brilliant device, and while limited, does do some things better than the Mac - annotating PDFs and ebooks with the Pencil being one of them. Also nice to hold a document one is working on in landscape…
Like all things Apple, iPad is great if you only use it for the exact, limited use cases it was designed for. The moment you start to be beyond that slightly it completely falls apart. Contrast it to a more general computer running macOS or Windows, which does a poorer job at what iPad does best, but it has a much longer tail where the complexity ramps up linearly, compared to the hockey stick of iOS.
Only if you stipulate that it was never designed to handle text editing, multi-object selection, and a number of other fundamental use cases that apparently no one at Apple bothers to do on their iPads — if they did, they’d either 1. Experiment to find better solutions; or 2. Admit that there is no good touch-based solution for this UX scenario.