Keyboard shortcuts: minimize, maximize, show, hide, make visible, unhide, activate oh my!

Sorry for the long posts, with multiple questions, but I think they are all related. 😕

1. I often, accidentally, set a window to Full Screen. The window fills entire desktop, with the exception of the menu bar. I want to be able to cascade two or more windows such that I can see both on the desktop. While still seeing some parts of the desktop. I'm able to minimize to the dock, by selecting the '-' option with my mouse.

a. What are the keyboard shortcuts for minimize, unminimize window. Typically in Win I would Alt-tab, and tab to the window I want to see. When I Cmd-tab and select, e.g., firefox, in Mac nothing happens. It seems the only way to unminimize from the dock is to use the mouse. Is there a keyboard shortcut? And is this really 'minimizing the window', 'hiding the window', or something else.

b. Does the Mac have the concept of 'saving window size' similar to windows when the minimize option changes to 'minimize to size X'? 'Size X' being less than full screen and more than 'minimized'? If so, how do I enable this concept? If not, is there some alternative that Macions typically use to go from full screen to 'Size X' screen?

c. Please describe the concept of hide X, unhide All, show all? And specifically why the 2ndary menu's do not have the complete set included. For example: If there is an option to 'hide X', I would expect there to be a 'unhide X'. X being window, application, all windows, all applications, etc.

d. What is the logical relationship between all the 'hide','show', minimize X, etc. features that I am obviously missing? There seems to be some logic to it but I am oblivious to it. And thus spend quite a bit of time looking for a window and trying to get it to display on my desktop. And then once its on my desktop, I spend more time trying to go from 'not-full screen-but-not minimized' and minimized.😢

Any help is appreciated.!!1

And yes, I have looked through the Mac 101, Switch to Mac tutorials. They mention how to do some of the functions I mention. But there is no explanation of the relationship between them/purpose for each. I'm sure they are not duplicates of each other. And lastly, it does not fully explain keyboard shortcuts. e.g., I think I found a keyboard shortcut for 'hide X' but then I didn't find the shortcut for 'un-hide X', etc.