You are right, the CH sound in
Charles and Mädchen sounds different. There are two CH sounds in
German, one is hard (like in "Bach" or "Loch Ness"), one (like in Mädchen) is soft. You would have to lift the back of your tounge almost to your palate to leave just a small gap for the air to slip through. The sound you produce now is voiceless.
This sound is very hard to produce for Americans I found and only few of those who speak very good
German really manage it. So
CHarles isn't the worst try.
I heard, in Arabic there are five or more CH sounds …