Ubuntu – Avro is installed, but bangla writting is still not coming

I'm on Ubuntu 18.04. To install Avro I first downloaded the latest version(avro_2.1-3_all.deb) from github using command

$ wget "https://github.com/ugcoder/avro/releases/download/v2.1/avro_2.1-3_all.deb"

Then installed:

$ sudo dpkg -i avro_2.1-3_all.deb

Then finally ran these command:

$ sudo apt-get install -fy
$ ibus restart

Before these download and installation, I entered "Language Support" and ensured that the box for Bangla is ticked in "Installed language". Also ensured that Keyboard input method id IBus.

Now once avro is installed, I went to settings and added Bengali(Avro Phonetic)" as input source.

Now I opened LibreOffice Writer switched to Avro using super+space. Everything was set, only all that is coming are English letters. Same happened on gedit, same happening now: I wrote this whole question with Avro selected!

What's happening?

To enquire, I checked to keyboard layout of Avro Phonetic. Surprisingly avro's keyboard layout is identical to English(US)! I then manually downloaded the avro fonts and copied them to /usr/share/fonts/truetype and restarted my PC. The result is same. Now what can I do to write Bangla with Avro?