You need to throw out the breeding mechanics because there's tons of contradictory shit that don't make sense, or exist for balancing reasons. Obvious male/female legendaries that don't breed, Nidoqueen, Manaphy/Phione, pre-evos and babys, superuniques that don't evolve (Eternal Floette, LGPE Pikachu/Eeevee, Ash-Grenigger) the arbitrary nature of egg groups and egg move daisy chains.
The anime/basic logic is a lot more consistent. Pokemon are different species, so they have their own life cycles and biological limits. Evolution is a species swap. Similarity to "metamorphosis" is merely that, similarity. Real-life animals don't change species when they undergo metamorphosis, so Necrozma using Utra Burst is closer to a real-world butterfly life cycle than the caterpie/metapod/butterfree evolution chain is.
There are big ass, Venusaur-sized Bulbasaurs in the anime. Doesn't make them Venusaur, makes them old, fatass Bulbasaurs.
