Same for me but the App Store page for the app still says Twitter. Changing it there requires approval I think.
Similar to maximize but it tries to expand the window only enough to show all the content without needing to scroll.
Although the functionality is still abysmal, you can also double click the title/header bar to Zoom.
Would you recommend running another Fediverse microblogging software like Pleroma or Calckey? They can use/interact with all Mastodon features just fine. The issues you found…were they Mastodon-specific or Fediverse/ActivityPub in general?