'in order to...' - ற்காக -vs- வாறு

I've been wanting to ask for a long time.. to what extent is there a difference between using "ற்காக" and "வாறு" in order to convey the in order to sentiment ?

In trying to find an apt example, I feel like my questions might've been answered thanks to this video - https://www.youtube.com/watch?v=Hhx3jFAVj2Q&ab_channel=EnglishGalatta - but any additions (also through the eyes of non-natives who have their own quirky ways of seeing it) will be appreciated.