Gmail (Android App)
Works well with multiple accounts. Easy to set up with Gmail or with any IMAP-based email provider. Handles both light and dark mode, and is good at detecting when a message was designed for a larger screen and adjusting the layout so you can read it.
But it tracks you more than it should. In particular, any outgoing links are modified to route through Google’s servers first. And I have no idea what else it might be doing with info it gets from my other email accounts – never mind what they do with the actual Gmail account!