My understanding of why is that it relates to their change to a scene-referred workflow. Up to v3, darktable used a display-referred workflow like other programs. In that model the image you start with is mapped on a tone curve from the start where 0 is pure black and 1 is pure white, and the midpoint is set to midway between. This is all from the standpoint of what your display can render. The scene-referred workflow in v4 doesn't do that. All the tones are mapped in an unbounded and uncurved way. So images look flat, but you've retained maximum data, so you have more to work with. The developers assume that you want control and maximum fidelity. There's a better explanation in the intro of the documentation. This impacts everything - especially the color balance.

One of the problems is that all of the display-referred tools remain as modules in the interface, and some are even used in the base processing, but you're not supposed to use them. At least if you want to do things the 'right' way. We created a custom panel that has 90% of what we regularly use (shared UI with my partner). That plus creating some presets that work well with our cameras has made it very quick to get a satisfying output in a minute or less.

Honestly, if you want to do minor tweaks to a RAW and mostly want what the out of camera JPEG looks like, there are much easier tools. If you at least occasionally deal with really challenging photos, or you want to get creative in the processing of some of your RAW images, darktable opens up a lot of possibilities, while being free and open source. So I think it's worth the effort to learn. Shooting with a colorchecker helped us get the presets we wanted for a variety of shooting conditions.