So these ideas are the basis of modern monetary theory (MMT) i.e. the theory of modern money, not that it's a modern theory of money. There's nothing very controversial here, in that the "theory" is just a description of how things work when you have a fiat currency. The controversial parts are what you do in your fiscal policy once you think about things this way.
Stephanie Kelton is a vocal proponent of this style of framing. She's been an economic advisor to Bernie Sanders and is the author of "The Deficit Myth" which explains these concepts. She also gave a TED talk on the concepts.
Richard Murphy is a UK proponent who writes a blog and has a YouTube channel where he explains the concepts.
There are others, but these two are a good way in. Searching for them, and also the the phrase "Modern Monetary Theory" should get you lots of talks, interviews and articles on both sides of the arguments.