Earlier quoted context omitted.
On Notes: 1. If you copy some text 2. Select other text 3. Paste the text you copied to replace the selected text Notes will crash. This has been known for years. Also if you turn off all suggestions in Spotlight on iOS and just use it as an app launcher, it will still take seconds for Spotlight to show you the results. For something that's supposed to be an indexed look up.
I keep annual journals in Notes and I’ve noticed (on iOS) that the keyboard becomes increasingly laggy as the year drags on / as the note length increases. I can only assume they are synchronously flushing the file to disk on the main thread during the keyboard callback handler. I don’t mean to be rude, but that’s how an iOS intern would implement it.
A bad one maybe