There were no consequential issues with EPA or DHA until a brain injury occurred. Then, it was found EPA confused the ability of the brain's vascular system to properly heal, leaving cells a bit dysfunctional. DHA was seen as beneficial and truly helping in damage repair. In supplements, we usually get fairly more EPA than DHA. In our bodies, we can convert EPA to DHA, though, but it might be that processes to do that break down a bit, as we age.
Also, we don't pass much DHA or EPA into our brains, yet, our brains really need them. Processes to guide EPA and DHA into the brain can break down. People with the APOE4 gene (about 25% of the population) have this and they specifically do have transport mechanisms that break down early (late 20s).
There are specific ways to get these fats into the brain again. Plasmalogens and lysophosphatidylcholine bound to DHA and EPA get the fats there, through different mechanisms. My wife and I recently started taking these, a few months back. Specifically, they are a supplement with Hokkaido scallop oil plasmalogen and another with Lysoveta brand lysophosphatidylcholine.
We still take a teaspoon of Omega-3 fats on days we don't eat salmon or such, but we are taking the gel caps of the two supplements mentioned above, every day.
If trying to just optimize normal Omega-3 fat, I would favor getting more DHA and just some EPA, if not eating salmon or sardines.
Just wonder what Hokkaido scallops have that others don't have?
This is the only supplement with that in it I could find (Amazon):

It's 50 dollars for 30 gels!