Iirc the hard part is that not all protein is the same, and your body needs a variety to actually be able to use it which is near impossible to get solely from unprocessed plant based foods. So, modern chemistry to the rescue.
(This is what I remember from like an hour of research a few months back so correct me if I’m wrong)
That’s a lot easier to do than what I remember reading about, so thanks for the clarification!