You will want to populate the Name with the matching UploadLocation, which in your case will be the tmp location. And the Path you will want to specify the path of the file.
Your resolvePath looks like should be able to use the default implementation as it should use the prefix with uploads and then the location name by default.
Try removing the resolvePath, and then your API calls should specify “tmp” as Name, and path should be the original path/file name of the file. The /uploads prefix is handled by the plugin.