It’s interesting to see these pixelpeeping competitions for sharpness popping up every couple of years, screenshots at 100% are nice but there is nothing valid but uncompressed output files 
Especially in darktable some modules behave slightly different depending on available roi, at least compare screenshots with the new “toggle high quality processing” if you pixelpeep on screen.
Some years ago - ingo weyrich was still very active - we worked to implement capture sharpening for dt. After having the detail threshold for masks and the very good sharpening presets for D&S i just stopped working on that because i personally couldn’t see any significant difference at all. Just my 2c …
EDIT: forgot to mention, haven’t used art at all (yet)