Got some big buds but 2 plants of same seeds not producing same quality in same space grow

Agree with @Ezzjaybruh, Phenotype variation. this is why clones are great for scrog nets or sog style grows in the same tent. Good Luck!

Why are all my cousins over 6' tall while im 5'7 ?? we all have the same grandparents right? Or why is my of my cousins familys with 4 kids- 2 are white blond and two are dark brown? same parents... Why does my sister and I have diff eye color ? its just genetics- this is why pple started taking clones back in the day when any seeds, let alone good ones were hard to get. So when you found a really good plant that was better than the rest, u kept it, turned it into a mother plant, made more clones of it, made more mothers out of them and started selling the clones of that one really really special plant you found after going through dozens or even thousand's of seeds to find it. U could make as much money off a really good mother plant- clone business as selling bud when good genetics were hard to come by. Today good seeds are easy to get, but you still get genetic diversity- some will be shit. most will be average, some will be great and a few rare ones will be something truly special. Not every plant you grow even from the same seeds will be a good one. Some from unstable lines will have multiple phenotypes, one may lean towards the indica parent and finish sooner than its sativa leaning sister from the same batch of seeds. Unless growing from clones u will never harvest multiple plants at the same time. Even if its the same strain from same pack, one plant will always lag behind and one always seems to race ahead if you grow 4 or more of the same strain. fucks knows why... lols. may only be a few days or so buts its def visable.

It could be phenotypes. Or just a simple way you packed in the substrate. I overpacked 1 of my CBD seeds and she took her shape much early on compared to her sister, mind u 1 was soil 1 coco but my other coco is huge and it is much lighter than the CBD I harvested 2 weeks ago and her sister still has 2 weeks left, again dif sub but the contents were loose compared to the compact 1. Do w simple test. Pick up the unmatured 1 compared to the one that's much further ahead if you notice the 1 behind is much heavier you know it's down to compact sub. Any stable genetics should give near the same results if conditions and feed times/amounts/potency&sub layout are the exact same. Also you should move your plants around as plants in the middle of your light get a higher ppfd compared to the ones on the comers could that be a factor? Good luck buddy.

Like others said its phenotype. Just like humans the kids will be different and take on different traits from the parents.

The phenotype is very important, they are not descended from the same father. Also, the root development of the blooms is a big factor.

Phenotype variation