Generate 1k NFTs with rarity & upload to Opensea

I have my images ready and able to generate 1k images with json. However, there is no rarity in the metadata. So, I would like someone decently skilled to help me re-generate again where rarity can be inserted. Then, mass upload them to opensea.

Other developer suggest using screenshare. But I can do on my own too with your instructions. Let's discuss.