Blackboard would allow me to prepare homework solutions (or any file really) in advance and assign it a date to be made available to the students. i.e. assign any document a publish date, so I could "pre-stage" documents.
When I contacted Canvas help, they pushed me into using Modules, which is not as easy and does not have the file I want to publish at some future date show up in the folder I want it in.
I really am trying to be understanding, but Canvas is way to complicated. Please bring back Blackboard.