Although there's no overarching "Auto" function in RawTherapee, it will attempt to match the tone curve of the embedded preview, and I found that my images mostly showed reasonable exposures and good color by default, with plenty of detail, too. And there are a truly staggering number of manual controls with which to adjust your images. Thankfully, there's also very good (and multilingual!) documentation available on the RawTherapee website.