it somehow doesn't even ink to text on my iPad

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

Typing latency is measured in the tens of seconds.

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)