So I've created a villager farm with the purpose of creating wheat/seeds. But I notice that the villager started crafting bread, instead of throwing wheat/seeds to my other villager. Is there a way to stop this villager from creating bread, and only farm wheat and seeds?
Villagers who pick up wheat, won't share it with other villagers. They will instead bake bread and share 50% of the bread they have (if it's in large quantities) with others who need food. As far as I am informed making a wheat farm is impossible if you want to use villagers, due to the reason mentioned above.
You can, however, make potato or carrot farms with farmer villagers (the ones with brown coats and no other collars), but make sure they have an empty inventory - when new villagers are born after mating they have empty inventory until someone throws something at them. If your villager is planting stuff you don't want him to just walk around with him and destroy his seeds, you will then pick them up and he is gonna use up all of his supplies for planting.
After that, you can throw him the types of seeds you need him to plant for the farm. Keep in mind that farmers won't pickup or plant sugarcanes.
My advice would be, if you need the bread for your own consumption, to just instead make a potato farm.
I have made a wheat farm using villagers. I haven't seen anything like it yet on YouTube or anything. It's quite simple though. You just have to let the villager out of a locked house for a day. Give him some seeds and let him plant. Then when he goes to bed lock the door (iron door) and keep him inside for 2 days to let the wheat grow. Then have water break and collect the items in a chest but give the seeds back to the villager and repeat the process.
You need to use water flow from dispensers with a redstone system and hoppers with chests at the other end to reap the wheat before the farmer can clear the field then throw him seeds from time to time to keep his inventory full of seeds, he will reap and replant on his own but any wheat turns into bread and the water will wash away some of the seeds that would've normally refilled his inv... so topping off his seed stores is advised