Have a look at this one
Conversations (Encrypted, easy-to-use XMPP instant messenger for your mobile device) https://f-droid.org/packages/eu.siacs.conversations/
Yes, and it also consumes in stand by
I would add MonoclesChat as well, it's a fork of Conversations with some quality of life improvements. It's obviously thought to be used with the Monocles ecosystem, but works fine with whatever XMPP server ;)
I'm using yaxim, seems to be an oldie but goodie
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