Hello pradip999 :
While considering a reply to your thread, noticed it was located in
an unlikely low-traffic area in the Apple Support Communities. So
had it relocated here; to where newer Mac posts go & be happier.
The correct link to Apple Product Feedback hasn't changed:
https://www.apple.com/feedback/
https://www.apple.com/feedback/macos.html
And failed to add why I was interested. The font is used across several
languages and so that may be what makes it harder to find. 'Font Book'
in your Mac system should have reference, and the ability to switch to
see and use the Bangla typeface/font. Or add/remove fonts you prefer.
Closest 'Product Feedback category' was under macOS:
https://www.apple.com/feedback/
However you may peruse the link near end of this post
& see where else one may offer feedback to your inquiry.
• How to install and remove fonts on your Mac - Apple Support
https://support.apple.com/en-us/HT201749
Perhaps by perspective, Bangla may be considered a regional font?

However, found this in High Sierra macOS 10.13.6 in 'Font Book' app.
(In far north / N. America.)
• Font Book User Guide for Mac [Table of Contents] - Apple Support
https://support.apple.com/guide/font-book/toc
While this may be OK for this region; should you not find the
font or language typefaces of your choosing, please make a
note Apple Product Feedback; as indicated in earlier post.
https://www.apple.com/feedback/
Best regards & safe travels! ☺︎ ❄