Those who are facing problem writing bangla in 'Provat' layout after updating your Manjaro or Arch Linux system. You can just downgrade the 'xkeyboard-config' package to the version 2.29-1 to get over the problem. A link of previous version of the 'xkeyboard-config' package is attached to this post.
xkeyboard-config-2.29-1-any : https://archive.archlinux.org/packages/x/xkeyboard-config/xkeyboard-config-2.29-1-any.pkg.tar.zst