Problem is I am using TTS to read a long string message when my activity is launched, but TalkBack automatically reads the application name in the middle of it and cuts the long
In my case the app name was mispronounced by TalkBack. I fixed that by correcting the string name in strings.xml file.
Your App Name
What I previously had there was a name without spaces.
YourAppName
I hope that if you just left it empty or with empty space, you would get your desired effect.