Sorry, but your testing is faulty. Not everything you listed, but quite a bit of it. For example...
AquaMail does support POP3, it does have manual config, and it's just not possible to delete mail unless you tell it to. Also, default behavior is to ask to confirm delete before proceeding. And even if deleted, it's recoverable.
K9 does work with Gmail.
MailDroid can disabale auto push/check.
K-Mail does work with Gmail.
These are some I have used and can verify. Maybe you should give some a second try. Seems liike you're not spending enough time with some of them to understand what they are actually capable of.