It's the BBC. 'boss' as a mafia trope is specific to the US.

Yup. Similar to scheme, which doesn't carry the same negative connotation in British English as it does here.

I believe, the noun "boss", when meant as "a person who exercises control or authority", does not imply legal status or purpose of any group or organization.

https://www.merriam-webster.com/dictionary/boss gives an example of "union bosses".

thats what I keep telling the guy at the corner store