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.
If the definitions of the key terms and concepts in meditation is ambiguous, the body of scientific evidence of meditation doing anything is not particularly convincing.
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.