The only issue I have with Fetch is I can't get progress for up/downloading from it yet. Otherwise I prefer it over Ajax in every other way.
<a download href="example.com/my/download/route"></a>
and that always worked well for me. No idea if that would be helpful at all, I'm operating at a very surface level knowledge here.If this works, why isn't this documented in an obvious manner on something like MDN?