Developer needed - create a custom ERP/MRP program using AI/Github etc

We sell personalized giftable products. We currently use a mix between ShipStation and a lot of automation connections through API for Amazon, Etsy, Shopify, FedEx, UPs, et cetera. We use Google Drive to hold files. We're trying to automate our full process and be able to have everything in one place. We essentially are trying to create our own software as opposed to using SaaS. We're actually currently in the middle of implementing a software called Fulfill. The challenge is we're having a hard time customizing it to exactly what we want and I believe with today's technology this can be done much more simply, more customized, and cheaper. If you truly feel this is the right fit, please share why. Our goal is to have this set up in about 3 months or less. NO Agency - Only individual looking for full time work, this can turn into long-term work as we will want you to stay on board to enhance the system and help build more systems.