The paper you've linked to (https://sci-hub.se/https://doi.org/10.1177/1745691617709589) points out methodological flaws in meditation-related research, ambiguities in the meaning of "mindfulness" etc.; it doesn't set out to prove that meditation doesn't 'work' (in the sense that it causes no effects).

In fact the paper acknowledges instances of meditation-induced adverse effects; if meditation didn't do anything at all, why would anyone experience even adverse effects? Clearly meditation does have effects.