There's not really any evidence for this. On a source-by-source basis, plant-based protein quality tends to be a few percentage points lower than from animal so

There's not really any evidence for this. On a source-by-source basis, plant-based protein quality tends to be a few percentage points lower than from animal sources due to the differing amino acid distribution, but mixing sources like rice+pea gets you all you need. Soy is already pretty good by itself if you're okay with just consuming a tad bit more. Personally I just add a protein shake to my diet and that more than makes up for the difference relative to my carnist days. The micronutrients that vegans need to watch out for are EPA/DHA (types of omega 3s) and Vitamin B12. Both are trivial to supplement, and not particulary expensive (especially now that Costco sells the former). The B12 you get via factory farmed meat is all supplemented to them anyway, so there's no difference in some hypothetical molecule quality. The last remaining micronutrient that might be tricky is Vitamin D3, if you don't get the necessary sun exposure. The D3 in standard supplements is usually made from sheep wool. But you can also replace that with relative ease, and many vegan options are really mixed D3+K2 supplements which is even better. Also available at Costco, for what it's worth.