how can I find the Telegram user msg not bot (initialized by user) in flutter?

Question

I want all the messages (send/receive) from the user (Not Bot) to get some specific groups massages in my flutter app.

Note: I have a user name.

Can it be possible Please guide me about it?

I can get messages from the bot and send messages from the bot. But not know how to get user messages from the user id.

Thanks