Hi Masoud,
Obsidian can definitely do that kind of job, connecting ideas and facts (just like a detective in an movie as you said) and that’s what makes it special ,and better than, apps like Evernote.
For clipping websites you can use extensions like this one . Altho it’s still under development, and can improve, the app is new and in beta mode, so it is going to get better.
And Markdown is not a complicated terminology. They are like .txt files but just use some characters (Markers) to add stuff to the text. like using ‘*’ to mark a word as bold. They are much easier to use because you can use them and copy past them very easily.