You may be (inadvertently) ignoring JPEGS. The reason for this is that JPEGS alone are a terrible source for High Dynamic Range work. It is a lossy format (information is thrown away in the interest of compactness in compression) and very little information about image dynamics survives. Cameras often create “JPEG Previews” of raw format images so that conventional photo viewers can present something about a raw-formatted image for identification purposes, but not for use in a workflow. For this reason, Darktable can be set to ignore JPEGS, assuming them to be for preview purposes only, and that you really wish to import raw-formatted images, which are rich and detailed enough for HDR work.
If all you have is a “JPEG” stack, then I fear you won’t have very satisfactory results no matter what tool you use. Most of what is useful for HDR work has been compressed out of your images. However, something is better than nothing - check the Darktable user guide for enabling JPEG import. If you go the Darktable route, ask questions in the Darktable section of this site; I am, by no means, a Darktable expert - but over there, you have the real pros.
I would also thumbs-up @Entropy512 suggestion regarding HDRImage. it is worth a look and there is a dedicated forum here as well.