Check out Bruce Williams' YouTube channel. He has a nice workingman's approach to Darktable and a full selection of videos. While he's not as in-depth or technical as Aurélien Pierre, he's a lot less complicated and easier to understand. I spent a lot of time on his channel during the first COVID lockdown. It may not be the end all, but it will absolutely shorten your learning curve. He has 80+ videos and most are based on specific modules. Keep in mind that some modules have multiple episodes and older versions are only applicable to earlier releases of DT, so make sure you're watching the latest version.
Bruce Williams Photography - YouTube
Bruce Williams Photography - YouTube