In all honesty, Atticus isn't yet perfect for poetry, mainly because indents are designed for writing a novel. This is something our team is actively working towards to ensure all writers can comfortably use our platform.
Some options you might experiment with would be alignment blocks like hanging indent, block, or verse. Of these, hanging indent would probably be most useful for varying the indent. A hanging indent is a formatting style where the first line of a paragraph is flush with the left margin, while all subsequent lines are indented, following more traditional poetic line spacing.
If your poetry requires more than one level of indentation, the best option might be to create the poem in a design program like Canva or BookBrush and import it into Atticus as an image so the layout will be maintained.
Hope this helps!