keeping page breaks in an ePub for poetry

KDP allows FXL EPUBs, but put shortly, it's a format that should never be used for anything, especially not text-based books. So you're right that reflowable EPUB uploaded to Kindle is the right path.

Unlike print layout, where you can use sticks and glue and paper clips and whatever to stick text and elements all over the page, e-books require a meticulous structure for a successful export. So you will have to format your little book using rigid Paragraph Styles (as well as keep it in a single text flow, but that's likely not a problem here.)

If you have odd line arrangements, the only way to transfer them to EPUB/Kindle is to create a style for each line type, and apply it. I'd guess you'll need at least three or four "body" styles, something like —

• A first line, indented as you prefer, with space above as you prefer.
• A body line with normal indent.
• A body line with different indent.
• (Repeat as needed, depending on how elaborate your stanza structure is.)
• A last line, which may or may not have any special characteristics from a "body" line, but with spacing below as needed.

In general, spacing above is preferred as it will disappear at the tops of virtual pages.

Each of those styles should have the Keep Options carefully set to try and keep stanzas together; this can be tweaked by writing some CSS code for export but that probably won't be necessary.

It is entirely possible to do this from one ID source file, but it gets into some slightly advanced techniques. Would be a good learning project for such "dual format" layout, though. I'd consider starting afresh with your print layout, converted to the multiple-style format, and then doing the conversion to EPUB at the export stage, so you have one and only one source document to manage.

Let me know if any of that needs further explanation. But you can't get away with things like soft paragraph breaks, tabs (don't export), multiple spaces, etc. Everything has to be completely managed by that line's style.

Oh, and do NOT use the trick of breaking content into multiple text boxes, as to position a title or the like. Bad practice in every way, and fatal to successful EPUB export. One continuous flow, completely managed by styles.