I had been using the Gmail client on my Android phone because the user experience is not compromised in any significant way, at least speaking relatively. I would like to use a FOSS client, but I've found too many focus on functionality and not design and/or UX.
Still, Gmail has one major problem though: on accounts working through IMAP, you lose the Swipe to Archive gesture. This is pretty annoying as I've got two accounts working through IMAP. They receive a bulk of my actionable email and my default action is to archive email. This is a problem.
Finally, I decided to install and try Outlook. It lets me customize the swipe actions and doesn't lock me out from a first-party experience just because it isn't a Microsoft/Outlook email account. In fact, it feels better designed than Gmail and I think I'm going to stick with it.