How do I make my pdflatex .pdf compatible with Ingramspark

Yes, there IS a correlation with LaTeX!

Have a look at the novel document class package. There, you will learn how to convert a cover image into CMYK at 240% ink limit. For that part, you do not yet need LaTeX.

Then, if you have LuaLaTeX, you can use the novel document class to convert the above CMYK image into PDF/X-1a:2001 with Output Intent "US Web Coated SWOP v2" (or some other choices).

That's what Ingram Spark wants. That's what you get.

Absurdly detailed instructions in HTML format, in the document class package. Also contains some useful support files.

EDIT: This document class has been successfully used, more than once, for this purpose. Although the printer wasn't Ingram Spark, it was a similar print service using the same technology.

The novel class can do two different things: (1) It can create the book text block (not in color, no bleed) using LuaLaTeX technology. It is pre-set for the most popular requirements of American softcover books, but you can easily change things using understandable commands. The result will be PDF/X-1a:2001 unless you tell it not to do that. Verified using Adobe Acrobat pro. (2) With auxiliary free software (Windows, Linux, Mac), and scripts that make it all no-brainer, it can convert a color cover image to CMYK at 240% ink limit, then covert to PDF/X-1a:2001. This is independent of how you do the book block. So, you can write your book using a different document class, then just use novel for the cover, if you wish.

Visualize this as a much larger (cover size at 300dpi) RGB image. I created it in GIMP. It is sized to include bleed:

Then, after processing via novel instructions, here is a screenshot of the PDF/X compliance report from Adobe Acrobat Pro:

The above report does not mention ink limit, but that can be separately investigated in Adobe Acrobat Pro, and I assure you that it complies. The color specification "DeviceCMYK" indicates that no ICC profile is attached to the image. None is attached to the PDF, either. For grayscale interior, it is "DeviceGray" instead.

One other thing: novel does NOT do e-books. Never will. Print only.