Okay, I've actually managed to listen to your Youtube now (my first reply I was away from home and didn't have decent monitoring.
Before I get into microphones, I think you have bigger issues than the mic itself.
First, the acoustics of wherever you're recording are not up to radio standards. Radio
studios are very dead--with music you can get away with some room tone but for pure voice work you don't want any.
The studio building section here gives good advice--but remember it's aimed at music recording where you want a little room sound. You don't want any. Alternatively, if you can't build out your room, I've had good results doing voice recordings using an sE Reflexion Filter. I have
the original, more expensive one but I hear the project
studio version is pretty good. However, you have to be vewry careful to follow the set up instructions exactly.
Second, I don't want to seem insulting but a big part of the radio sound is your own voice. You need to practice your projection and using your "chest voice" rather than your "throat voice". Some practice in this area can make a big difference.
Now, mics.
If you really want the "American" sound but don't like the SM7B, give the EV RE20 a try. It's used in a ton of American radio stations and, being a dynamic, will also pick up less room sound even before treatment.
However, the British radio sound (as mentioned) tends to use a lot more condensers, typically:
BBC Local Radio – Neumann TLM102 or TLM103
Larger ILR \ Commercials – Neumann U87 Pres Mic & AT4033 Guest (or, sometimes, the TLM102/103 again).
Most ILR – Audio Technica AT4033 or Rode NT1A \ Rode Broadcaster.
However this is only a guide and you'll find other LDC mics in use too.
However, before spending money on the mic, I'd address the acoustics issue then try the Yeti again. It's not a bad mic for the money and even an 1800 pound mic like the U87 isn't going to yield the results you want in a reverberant space.
Hope this helps.