Chinese TV is very difficult to understand. Remember that.
世界青年說 is good, but they all speak very quickly, the topics are quite complex and they have foreign accents. (Especially the guy from Thailand, whose pronunciation is terrible).
To be quite honest, one of the easiest people to understand is 習近平 because he speaks slowly and there are always subs to his speeches and addresses.
邏輯思想 is quite an interesting YouTube channel, but again it's pretty complex stuff and kinda colloquial language
北京話話北京 is interesting and I love the presenters voice, but it's again kind of complex and full of slang.
鏘鏘三人行 is good, and I like 竇文濤‘s voice, but again it's complex and there aren't any subs
我是演説家 is really interesting, they have a bunch of different people on there from all over China and Taiwan
非誠勿擾 is the Chinese version of "Take Me Out", a British dating show. It's easier to understand because you can guess what's going on, I find it super boring though. I suppose it's got some useful flirtatious vocabulary in it
Dramas are easiest to understand I suppose, but they are boring as hell