How to get a Windows 10 Home .iso?

I bought a used Surface Book over a year ago and have been using it fine, but its come to reformat it. The problem is that it came with an expired/deactivated Windows 10 Enterprise license. I have my old Home Edition key from the machine I was using before this, but the media creation tool refuses to work (I assume because I’m running on a deactivated Enterprise key) so I can’t get a clean ISO. I downloaded the Windows Insider ISO, but it didn’t specify which version it was installing so I was wary of wiping everything just yet. Could anyone shine some light on what the **** is happening? I’d really like to avoid getting an ISO off a third party website…