Hi @Sau5er5, welcome to the Forum!
So my starting point, when it comes to the early chapters of Genesis, is that they are not meant to reveal literal history but instead are designed to point to larger truths about God, man, and nature. This, for me, applies to all of the “primeval narratives” (Gen 1-11). So when I read about God restricting diets to plants to Genesis 1 (and then allowing meat-eating after the Flood), my question is not, “how does it fit into scientific/natural history”, but “what role does this imagery play in the story, and what can it tell me about God and humanity?” And honestly, I don’t know. It’s not an issue that I’ve personally studied. Diet is a big deal in the Bible, so I imagine that its related to this motif. As someone who has a seminary degree, this is a bit embarrassing. Let me ask some Bible scholars I know and get back to you.