Take this fwiw. I was a strict vegetarian for 15 years. I finally started to eat fish, after a lot of research over years of wondering (but it was a long time ago, and science has moved on), when we decided to try for a child. There was enough evidence to convince me that optimal nutrition, omega 3s in particular, could not practically speaking be had from what I was eating. For a little while I used supplements, but I came to feel that that just made no sense for me: none of my complex reasons for vegetarianism actually applied, actually bound me, if I felt I had to take supplements to compensate for deficiencies in that diet. YMMV, e.g. it's bound to depend on what your reasons are. And it did take me years to get to a point where I could actually see fish as food! But I enjoy it, with care for sustainability, now, and don't regret the change at all. Just fwiw.
I do always hesistate to mention our diets b/c I know that there are a lot of others who have differing opinions. I also understand that you're not pushing your choice as the only one. I, actually, don't feel that supplementation is needed in my instance or for dd12, who is HG and thriving. Dd10 has a strong genetic component playing into her attentional issues (from her dad). We eat a pretty good balance of O-3,6, and 9 in general, but I think that she may need something more or different than the typical person.
