The 2020 study that CNN cites established cohorts that included marijuana users who also smoked tobacco, marijuana users who also consumed alcohol, marijuana users who smoked tobacco and consumed alcohol, and marijuana uses who didn't smoke tobacco or consume alcohol.

There is broken down analysis in the study, and it suggests that consumers of marijuana, whether they were tobacco smokers or alcohol drinkers or not, have increased risk of heart disfunction.

All that said, I'm not defending the study, nor am I disagreeing with your sentiment.