Half of that complexity springs from the requirement of being able to put any element as the radio button. If you’re willing to say “you can only use anything that can be expressed with CSS applied to the <input type=radio>, including psuedoelements” (which is plenty for thing like shadcn), it melts away.

The other half of it looks to come from an overloaded Label component which should probably have been split into two. There’s a reason that HTML has <fieldset> and <label> as different things. The implementation is also trivially incorrect: role=label isn’t a thing. Other parts of it are wrong or dubious too. In general, if the HTML way of expressing something isn’t permitted, the ARIA way of expressing the same thing is probably wrong too.

And so it goes, through the entire system. They assume you might want something ridiculously complex, and so they complicate and make worse the normal case.