I’d like to suggest a button for creating the set of backticks for a code block, or if it’s already there, make it more prominent.
I’ve noticed that newcomers have trouble using code blocks, even though the help post template comes with one - this might alleviate that. There is a button for blockquote, so why not code block?
It’s equally hidden on desktop, and “preformatted text” isn’t the menu item I’d be looking for - maybe putting it among the default buttons (I think it trumps blockquote in importance) and calling it “code” instead?