MacBook and poor support for Tamil Unicode fonts

I have been using a Mac since 2004, I am writer in Tamil, and type a lot. My experience with Mac and Tying in Tamil is never been a good experience.

I use Notes, Text Edit and Safari (FB Posts) for typing in Tamil. Out of which Text Edit is somewhat OK but the overall experience with Notes and Safari is poor and many times annoying.

I suspect the main issue is with the memory where, copy paste, cut, insert, and delete (backspace) are of terrible experience.

How do I explain this to someone in Apple support?

Thanks