Excellent article by a person who, imo, knows as much about EPA and DHA and their MOA as anyone, Preston Mason, PhD.
A summary of all the evidence was recently published in the prestigious medical publication Annals of Internal Medicine.
published July 9, 2019, examined the effectiveness of 24 supplements
and diets in preventing cardiovascular disease. The authors evaluated
nine systematic reviews and four randomized controlled trials, which
encompassed 277 trials and 992,129 participants. Findings indicated that
few nutritional supplements or dietary interventions offered any
protection against cardiovascular disease or death and that some may
actually cause harm. Omega-3 products, in particular, yielded
“low-certainty” evidence that they were associated with reduced risk for
myocardial infarction and coronary heart disease.