"Anyone with the link can edit" only works if your organization allows anonymous access. Most don't for obvious security reasons, and Msft's language about this type of link is as usual confusing. Does the link work in an incognito window with no user signed in at all? If so, and you've also tried the file viewer web part, it's likely Msft is blocking the content from being iframed.
Hi webbrewers
I have tried a couple of workbooks and they both show up as expected in incognito browser windows. The iframe content shows correctly when I am logged in to my site (Wordpress), but when I am not logged in as an administrator then the iframe content does not show.
I will escalate this to support to see if they have a solution.
Thanks
Darren