k9, pop, leave on server
They may prefer to drop pop, but not yet.
Some settings: Redirecting…
Remember to check the option to Leave messages on the server
Also look at (complicated) folders settings, follow links from: Redirecting…
Termux may only work for Android 7+, but has old school email options too.
~ $ pkg search pop3
Checking availability of current mirror: ok
Sorting… Done
Full Text Search… Done
fdm/stable 2.0-2 arm
A program designed to fetch mail from POP3 or IMAP servers, or receive local mail from stdin, and deliver it in various ways
~ $ pkg search email
Checking availability of current mirror: ok
Sorting… Done
Full Text Search… Done
aerc/stable 0.7.1 arm
A pretty good email client
alpine/stable 2.25-3 arm
Fast, easy to use email client
mimetic/stable 0.9.8 arm
A C++ Email library (MIME)
notmuch/stable 0.32.2-2 arm
Thread-based email index, search and tagging system