If you want to write/reply to old-style plain-text
email from a
fondleslab, then use K9Mail. It is the only mobile client I know of
that can handle bottom-posting, trimming quotes etc.
Well K9 is getting a number of recs here so I will take a second look at it. I looked at
it initially but then saw it hadn't been updated since 2018. However, looks like there
is active working going on and a new version is slated for release sure (BETAs are
available for evaluation).
-Ali