We can't even necessarily claim that oily fish is "super-healthy". People shouldn't rely on it as their only source of protein due to the risk of heavy metal toxicity, especially for larger fish. A few servings per week are probably fine depending on the exact fish species.

https://www.healthychildren.org/English/ages-stages/prenatal...

Some plant proteins are "complete" in the sense of including all essential amino acids, but the ratios are wrong which still leaves at least one amino acid as a limiting factor. It's usually best to mix at least two plant proteins instead of relying on a single one.

Everything in moderation.