I work for a company which uses InDesign for webtoon-style comic content. These are often extremely long vertical images (10000-20000px is common). When attempting to export to JPG/PNG for processing, InDesign will not process the larger files, claiming that they exceed the maximum size, even at resolutions as low as 200dpi (webtoons typically go online at 350dpi so these images need to be upscaled).

Exporting to PDF and re-exporting to the relevant image format allows the images to export at size, but often with additional scaling and does not 1:1 match the original pixel size.

This clearly isn't a limit to the file spec but to the engine.