I write mainly short stories and poetry, and am unsure of what social media platform will garner more attention to this type of writing. Is there a tried and true social media that will get me more attention than another?
There is no perfect place. No social media platform is going to give you attention just by posting there. The internet is full of Stuff for people to read; they aren't queuing up to read your material. Anywhere.
Wherever you're writing, you'll need to build up an audience. You'll need to establish some kind of platform, a home base, and find places you can publish your work which will get it read, and ways to promote your work so people go read it wherever it is.
Some platforms are better than others; different ones can have different pros and cons. But no platform will provide you with widespread attention, unless you go out and get it yourself.
Forget about promotion. Just write your stories. Submit them for publication in journals and magazines. (I much prefer getting my stories into print rather than getting them online.) If you get to the point where you're working with a publishing company (say, on a book), they'll advise you on how to promote yourself and your work.