I think that the conversation on degrowth is evolving among marxists, but there is a kernel of malthusianism in some degrowth arguments that is fundamentally reactionary. https://www.liberationschool.org/degrowth-a-politics-for-which-class/

"The reality is that, in developed capitalist countries like U.S., there is an overabundance of material wealth and that scarcity is socially produced by the capitalist market and private ownership. Degrowth is correct on the point that if wealth were redistributed then there would indeed be abundance. However, even though proponents of degrowth are well intentioned and truly want to solve environmental crises, the political-economic methods and solutions that degrowth calls for actually work against creating the critical mass necessary to make a socialist revolution here in the U.S. I address each of these below by showing how 1) degrowth reproduces Malthusian ideas about so-called “natural limits;” 2) it’s anti-modern and anti-technological orientation lacks a class perspective; and 3) there are key practical issues with deploying degrowth ideas in the class struggle itself. "