Can I upload multiple products?

Is it possible to upload the same product as template and once as a complete project and each product has a price?

No, you can’t. Same product with different template mean same item not a different item.

Does this mean that if I made a project as a flutter template and it was accepted, I could not develop it as a full project and re-upload it to the full application ??

Or now the template project different than full application