I am able to upload many files using the below approach
const formData = new FormData();
inputs.files.forEach(({ file }) => {
formData.append(`files`, file, file.name);
});
const data = {
...someData
};
formData.append("data", JSON.stringify(data));
Looking at your request it is difficult for me to say but have you tried something like:
formData.append('files', fileStream, 'myfile.jpg');