Thanks for the suggestions, I had turned off sharpening but not the base curve in the core options yet. I have tried and used a style to “pull up” the relevant modules for a filmicRGB-based flow and disabled the base curve this way as well. However, for a single style to work to pull up modules into the first tab, I had to turn on everything I potentially wanted to use and thus this slows down initial adjustments. Later I discovered the presets defined in the ‘more modules’ menu, but it is far from obvious how to customize any of it, and the handbook doesn’t seem to mention this feature at all. This seems to be the most fitting place for what I’m looking for, in conjunction with the core options to turn off the base curve and some module presets which auto-activate.
I do have an entry in the “more modules” presets mostly fitting my needs - but don’t actually remember how I got it in there, nor how to make any adjustments to it now. The manual only contains "However, you may store various settings at your choice as presets for later reuse. " in the “More modules” section, there are edit and delete preset menu items (which only seem to edit the name), but no option to add a new one based on the current selection of module visibility.
Maybe a predefined workspace and/or subset definition in darktable-3.0.1/src/libs/modulelist.c for modules, which do make sense in conjunction with filmicRGB would be useful.
Altogether, core options + styles + module presets + module visibility and or favorites settings + maybe turning that into “More modules” presets all may come into play. Quite a few things to fiddle with in order to create a “smooth” user experience for a filmicRGB flow after having learned about which modules to use or avoid in conjunction with it.