[breput]

There are legitimate studies that correlate increased CO2 levels with decreased performance.

https://pubmed.ncbi.nlm.nih.gov/25117890/

[learc83]

There are also many more legitimate studies (and decades of experience) showing that submarine crews working at an order of magnitude or more of CO2 concentrations experience no cognitive effects.

It’s very likely the study you linked is flawed or there is a confounder.