How do I explain my job role?

I see people keep telling they work as frontend, backend and fullstack. But I feel these are more of Web developer roles. Then comes Devops, Data Engineers, Data Scientist etc. Where do I fit ? My work is follows -

1. Pick a story from sprint
2. Story as small as writing unit tests or functional test for some logic
3. Solve a small problem related to the product such as - on a certain scenario NullPointerException occurs . So debug that and fix it.
4. Add a new feature to already existing functionality - e.g. collect more log information, extend product to cover more scenarios etc. What exactly will I say my work is? Backend - come on.