MMT is both novel and correct. The problem is that the novel parts aren't correct, and the correct parts aren't novel.

Have a look at https://www.econlib.org/library/Columns/y2021/Sumnermodernmo... for MMT.

I suggest having a look at market monetarism. See eg https://marketmonetarist.com/2015/07/14/the-euro-a-monetary-...

What kind of orthodox economy theory have you had a look at?