They're already using 4.5GB... You can upload multiple files over 1GB each. "Go!Go!PizzaBoy!" is, for example, almost same file sizes and structure. If the dev is using butler to bypass the default 1GB limit already, they should be able to use it to upload the files separately by using channels. https://itch.io/t/1916522/how-to-upload-for-multiple-platforms