We have the same exact requirement @jhecker and @klincecum helped collaborate on a thread: Sales Order Testing - Adding Bulk Releases - Kinetic 202X - Epicor User Help Forum (epiusers.help)
check that out like @timshuwy had said.
I also talked to Six S and they alluded to some type of tooling created by Epicor to help with the loading of massive amounts of releases (something custom not shipped with Kinetic). Obviously it’s by their customization group so you’ll need to pay for it and it may not be exactly what you need so you’ll need to tweak it further. If you want me to connect you with the people I was talking to let me know. I never proceeded with the conversations because I got pulled away to work on something else, but we are 1000% interested in a way to do what you are doing with 1000s of releases and not see this slowness.
Shoot, if you want to split the cost between our companies so we each get a tool to load and maintain thousands of releases on an order maybe we could unite!