Hi @Mike71,
This exact feature is one I always point to as a bit of a cautionary tale around feature requests... In earlier days of Canvas, there was a very simple "mute" for each assignment in the grades area that when enabled would hide all grading activity for that assignment. Teachers could "unmute" when they were ready and any grade info was revealed to students at that point. Muting could be done before any grading happened, but teachers would need to remember to do that step before they started grading. Muting applies to all grades for a certain assignment, regardless of what section a student was in, and couldn't be changed on a per-student or section level at all. It was fairly simple, but effective (especially for schools/institutions with smaller classes).
Then, after a ton of feature requests for more control over grade/comment hiding.posting, Instructure released the current system in July 2019. While I think teachers of larger multi-section courses appreciate the features the current system added, it definitely added complexity that a lot of people still don't understand to this day. The mew system allows teachers to set up behavior from future-entered grades (posting policy) vs already graded things (hiding), and allows posting to certain sections, all of which segments of users wanted. Those who liked the simplicity of the old system basically had to learn the complexities of the new...
Now, aside from comments, I can tell you how I usually talk to teachers about this... I'll generally say the grade posting policy is how to control what will happen when grades are entered in the future. The Hide grades option only controls what has already been done, and that even comes with a big caveat... Many students have grade notifications configured, so they get their grades emailed ro delivered as an app notification as soon as they are released... While hiding the grades will keep them from being displayed if the student goes to the Canvas grades area, many will have already gotten their grades via other means.
So overall, the flowchart @Gabriel33 does seem to be basically correct still today. It may make things look slightly more complex than they really are, but this isn't totally simple anymore. I do think it's important to point out that the complexity is the result of a lot of user requests... I do't envy the folks at Instructure who have to evaluate ideas, prioritize them, then implement them, as it's got to be a very hard process. There is hardly ever one solution everyone will universally like, and even though I myself advocate for options at times, I also realize that having too many options also can result in a product that's too confusing for anyone to figure out.
I don't know if this info helps at all, but I thought I'd offer a bit more on the history around this particular feature.
-Chris