How is best to manage products that are pre-orders as a seller?

We’re new to Amazon and have only been selling on the platform for about four months.

We’ve recently stocked up on some collectible products from our wholesalers that we’ve listed on Amazon, and the sales for these products are coming through thick and fast.

Before shipping, we’ve realised these are listed as pre-ordered items on Amazon and therefore we’ve held off on shipping them. Some are available next week, others towards the back end of December.

Problem we’re facing with this now is how to manage it. I’d like to mark them as shipped just to get them out of the “unshipped” pot, but then ship them a few days before release. But I don’t know if this would confuse customers?

Or do we let them sit in the pot and ship them closer to release date?

These products are also available now without pre-order on other websites, so I’m torn on shipping them early, or would this cause issues with Amazon?

I know this sounds stupid but I generally don’t know how is best to manage it overall. It’s not something we’ve encountered before