Swatches For existing variable products!

Hello,

In my site, I import products directly from Printful (https://www.printful.com), they have a plugin and my site is sync with their site. The existing products, imported on my site already have color and sizes. So, I make in attributes, colors and sizes, but they are additionally not replacing existing attributes, and if I delete all existing and create another from all variables, that product will appear “not sync” And I cannot sync from their site to mine because every product have a order number and cannot be sync. Here is the product on my site https://www.editive.eu/product/parrot-sweatshirt-2/ . And worst of all I have to add the images in 50-60 variation manualy.
So…there is a way to merge or sync the new attributes with this old attributes? I desire to add colors and sizes and work automatically. I mean : If I add a red, white, blue / size L, M, S – T-shirt, I want the swatches to appear in place of dropdown boxes, without to delete existing variable imported from Prinful site.

Hope you understand,

Best regards