Love the article, and like you, I love my iPad Pro. I had the original 2015 12.9 pro and updated to the 2020 version when it was released. I have a couple of comments:
Device Conenctvity — that USB port on the multiport AV adaptor (HDMI/USB-A/USB-C power) can accept more than just USB storage devices. I have used it to connect an external Zoom microphone, and on my old iPad I used it to connect my Olympus EV-500 camera provided the camera has a USB storage mode so the iPad thinkis it is just another storage device, where you can access the files on the camera directly through the Files app.) So — more connectivity than you think.
Airdrop — I used it a lot — if I have a big video file on my phone, I will just airdrop it to the iPad rather than waiting for it show up through iCloud.
Having that second monitor be its own display would be nice, but some apps support using the second display outside mirroring. You mentioned Luma Fusion, which can put the preview on the external display just by clicking a button in the Luma fusion display. MindNode uses the second display to show the entire mind map you are working on. So, it is possible — but on an app by app basis.
Finally, I have the MAgic Keyboard for the Pro, and I like it a lot. If you put the Apple Magic Keyboard for your Mac up against the Magic Keyboard, the keys and spacing are the same. The “Fn” key on the Mac keyboard is a “globe” on the iPad Magic Keyboard, for accessing emojis ad other such stuff. You can also remap any of the modifier keys to do different things.