Medium isn't a great place to publish fiction.
Very few people come here to read fiction. So even if it's good, you won't get much traction.
I reposted a dozen short stories to Medium during the first year I was here. Even though they'd all done well when first published, and several of them won awards and made good money, none of them found many readers on Medium.
I'm not saying this to discourage you from posting short stories here but to give you a reality check -- if they don't do was well as you'd like them to, it probably isn't because they aren't good.
It's because the audience for short fiction isn't here.