NFT Polygon - Smart Contract

We are looking for someone to create smart contract(s) for NFT for our already generated images. We want to use Polygon to avoid gas fees. We want a customer to be able to select any of our already generated images and then gas fees would be passed on to the customer for minting the NFT after the transaction(s) have been secured and approved. We have an account on Opensea so whoever is hired for this would also need to upload everything to there. We have 10k images randomly generated from our base character ( with rarities ) and JSON and Metadata files for support. We also want royalties built into our smart contract.

We have a website already built in Squarespace
We want to avoid any gas fees OR pass those fees ( including any marketplace fee ) on to the customer when a sale is made.