I can try my hand at these once I have little bit of time :) Olympus has their JPG algorithms very well tuned, they do not set the bar low! Here are some tips:

• Turn on capture sharpen (it’s under demosaicing, give them a little bit of boost)
• You might also want to turn on diffuse or sharpen module and use something like sharpen demosaicing / AA Filter preset
• For photos like these where they’ve been shot (looks like) from a distance, there’s atmospheric haze, you might want to turn on “haze removal” module and see if you like the results
• I’m using a preview version of Darktable that has AGX -module (which I use instead of filmic or sigmoid) and I like the results contrast / saturation -wise but you might need to wait for a bit until it’s in the official release, until then I recommend using sigmoid
• I have my own 3D Luts I use for colors but to get somewhat closer to Olympus colors you could use “Rgb Primaries” module and tweak every hue little bit right (somewhat more for the green one) and add some color purity for each one of them (again somewhat more to the green one)
• For the shots at ISO 800 I’d enable denoise (profiled)
• After that I usually play around with “color balance rgb” (and maybe tone equalizer) if I still need more relighting / contrast / saturation work done

Once you get a basic set of corrections you think might benefit most of the images, create a new style and try applying that to more photos and see if it works… and tweak it along. It’s less exhausting to edit when you get a basic style down that provides a better starting point. Darktable may be a bit intimidating because of the berth and depth but you’ll get there eventually and you’ll be flying through edits :) (Also, don’t forget to hotkey stuff that you notice you use a lot, like cropping etc.)

Oh, almost forgot: if you want to see cool edits using Darktable I recommend watching some videos from Boris Hajdukovic.