Like everything else in life, it depends :
* I feel the key message here is "single vs multiple windows", not small vs big monitor. I love my 32" curved monitor. I too switched from having three monitors to having just one big monitor and staying with one maximizing window majority of time.
It's also role dependant. I spent few years as ops manager and multiple windows and situational awareness / task parallelization were important. Not saying it's a good thing but it was the name of the game.
Even without task parallelization, multiple windows are important for some roles. If I'm transforming a working excel into executive slide, it's nice to have them both up. If you are good at taking notes, having teams meeting and one note up is a life saver and super power. Etc
But yes - I think core message is "do not assume that prevalent wisdom or what others do, works for your task, job, and personality". As another example, I think dark mode is cool, all my cool friends use it, and it does not work for me on majority of applications. And that's ok... Not everybody is cool like that :-)
one thing I've noticed with the "single ultra wide monitor" vs multiple smaller ones is that if I maximize something on the ultra wide the "important" part is often off to the left, not centered.
I actually redesigned my desk a bit so my ultra wide's left side is directly in front of me to compensate for this, which is a bit weird, but ... it's working so far.
An aside: I am generally good at keeping notes while in a meeting, and I have tried shared notes in One Note, but as soon as someone else edits something in the same spot, it creates a forked history requiring manual reconciliation: does this work for you?
I've switched to Word akin to how I used to do it with Google Docs as that works much better.
Perhaps it's given away by "One" in the name (one simultaneous editor)? Or am I holding it wrong?