I am currently trying to implement a custom document widget for the CaseDetails - this is nothing new, but in this instance, we have a document viewer which is sadly bound to the boundaries of the iframe it is displayed in:

As far as I know by reading the documentation, the iframe is mandatory and I can't do anything about it.
Since the customization of the portal is deprecated in LTS 12 for this component, I am not eager to do it this way.
Are there any plans to support embedding a process start or user dialog without having an iframe wrapping it?