Mandarin has a reputation built on the wrong difficulty. Its grammar dispenses with several things that make French learners work hard: verb conjugations, grammatical gender and agreement. The real obstacles are elsewhere, and knowing exactly where they are is what makes the first year survivable.
Most podcast lists for French learners are lists of podcasts in French. That is not the same thing. What matters is how fast the speaking is, whether anyone is making allowances for you, and whether the show still exists.
German has a reputation for being difficult and a habit of being long. It is also a close relative of the language you already speak — and once you can see the family resemblance, a great deal of it stops behaving like a foreign language.
French series travelled the world, and with them the idea that you can absorb a language from the sofa. The evidence says watching helps — but only under conditions almost nobody follows.
French is often described as the most carefully guarded language in Europe. Its vocabulary tells a different story: Arabic through Spain and Italy, Germanic from the Franks, Italian from the Renaissance, and English arriving in both directions at once.
The useful question is not which German drama is best. It is which German you will actually be listening to — how fast it is spoken, which decade it comes from, and whether the accent on screen is one you will ever meet again.
Beginners are told Russian is hard and shown the alphabet as proof. The alphabet is the easy part. The difficulty lies in three places that no first lesson mentions, and knowing where they are changes how you begin.