ctrl + s only works with the itch.io if it has html, if it's zip ur gonna need to get all assets and project.json to turn it into sb3. ctrl + s doesn't work with cocrea bc cocrea don't let u access to the html.
the only possible way to get unremixable cocrea mods is IF the remix button tells u can't remix it but it's not gray, that's when u get the project id for this and put it in the link (without remixing permission in the url cuz it'll prevent u from remixing)
yes this is how i found out u can get the assets from reddit post. i tried the extension before and it worked but now it seems it doesn't fully download all assets anymore since it keeps giving 1kb files..