Custom Steel Weight Plate for Vest - Sourcing/Supply Agent

Good Day Sourcing Agents! I am looking for an very experienced sourcing agent to help me source CUSTOM made weights for a fitness weight vest (prefered China, open for other markets). Specifically, I need help finding the RIGHT professional, legit, certified factory with service from A-Z (Sourcing, quote, sampling, negotation, production, maybe inspection,...). The estimated size of the order is >6000 pieces (3 tons, each piece has 0,5kg), target DDP price around 1-1,5usd (depends on quantity) so I need someone who can negotiate bulk discounts, manage shipping, inspect production, check bulk production,... and access providers who specialize in this type of order. I am looking for a professional sourcing agent with extensive experience in this field who can help me launch my product with confidence. Please describe your service as best as possible. I only can choose based on ratings, your work examples and description. Please see in appendix a drawing and a picture of some existing samples (we "produced" in China too, but after some problems we decided to go for a new supplier as we are really in hurry). Thanks & Greetings from Austria Fabian EVRACTIVE Sports