My impression of
Olympus Workspace was that whatever the changes, they didn't really make it any faster. Besides, from what I read, it won't run on El Capitan - it needs OS X 10.12 or newer, and El Capitan is 10.11. See here:
support.olympus-imaging.com
Anyhow, I mainly want to confirm that the
Adobe DNG Converter is a simple and effective way to solve most compatibility problems. Here's the best entry point for a download:
Information on downloading, installing, and using the Adobe DNG Converter to easily convert camera-specific raw files from supported cameras to the more universal DNG raw file format.
helpx.adobe.com
Other than that, there are various free RAW processors, the two most powerful being
darktable and, above all,
RawTherapee; but they both come with a learning curve; even though I don't know
Affinity Photo, I suspect that they may both seem rather intimidating at first, and certainly less polished (at least
darktable). That said, they both work well, and
RawTherapee is especially versatile and full-featured. But they're both their own animals, not mainstream at all. However, since they're both not only free, but
Free Software, you can try them without any penalty except on your own time. I prefer
darktable because it's easy to set up your personal workflow (which the software helps to optimise!).
FYI, the Attachment tag doesn't allow for orientation manipulation, either, so it's down to adjusting (or securing) orientation on your machine before uploading.
XnView MP may help you there - it's another versatile piece of software for image manipulation, and it's fast.
M.