"who is the single one contemporary person who took labour theory of value seriously in an academic sense?"
ChatGPT: G.E Cohen.
(G.E Cohen is an Analytical Marxist BTW)
Here's what G.E Cohen has to say specifically on LTV:
1. "labour theory is, moreover, false" [1]
2. "The labour theory of value is not a suitable basis for the charge of exploitation laid against capitalism by Marxists, and the real foundation of that charge is something much simpler which, for reasons to be stated, is widely confused with the labour theory of value." [2]
[1] https://andrewmbailey.com/money/readings/cohen
[2] https://www.versobooks.com/blogs/news/3128-the-labour-theory...
So here you have the one guy who took this flawed concept seriously, * from the side of Marxism * and then has to conclude that it is false.