Must be using the same GUI framework that they use for Office apps on Windows ;-)

I haven’t seen any such sluggishness. The only area where OneNote (MacOS) is slow is in syncing to other devices where it can take a minute or two to bring changes to another device. I rarely switch devices within a session so that doesn’t bother me.

Which OS are you using for OneNote?

You’d hate the Tangerine (bank) website. Each letter typed does a round-trip to the server, and each text box gets progressively slower the more put in it.

(Not just trauma-dumping. Saying this here to say there might be a common tech problem that we can expose)

It did on my Surface, for what that's worth.