Confusion over what seems to be inconsistencies with basic commands

Background: I have a different way of learning things. When I find inconsistencies, I have difficulty and often puzzle over the "why's." I'm envious of those who just accept things as they are. I can learn them, once I confirm that there is no logic to how/why they exist. For example if I was trying to learn how someone organized their papers, I expect a logical system until they say, "there is no order or logic. I just stick it in there." I can learn complex things when there is a logical system and consistency.

I started using computers with CPM & DOS, then moved to Windows and later Mac OS. I love my Mac for many reasons, but there are times I could pick it up and throw it against the wall. I have trouble with the most basic things for the Mac, that I must do dozens of times each day. If I want to turn the light on in just about any room, I look for a switch and move it from one position to another. Yes some have pull cords or some other methods but that works 95% of the time. We don't even think about it. But in the Mac World, it seems that one room has the wall switch, another one requires me to dance, and another room requires that i produce a tone at 44 mhz, or blink my eyes. I never know which.

ln particular basic file commands are done in multiple ways and I can never figure out which to use.

Examples:

To delete a file, I find the file and click the delete key. Other times I have to modify it with a ctrl, opt or cmd. Sometimes none of them work. Or I right click and select Delete. Or right click and select Move to Trash. Even within Finder this seems to change, I even think I remember using ctrl-x. I can't do these within applications such as Word or Numbers and have to open Finder each time.

To copy a file, I may click and drag the item from the original place to another. Sometimes it copies....sometimes it moves. Or I can ctrl-c, ctrl v. I may have to hold down the ctrl, opt, or cmd, or use the menu bar.

To copy a photo, I do it one way from a document, another way from the internet and another way from photos. I may have to start by exporting it from photos or doing a screen capture and saving as a file. CtrlC/V works with one, Insert commands in another, or dragging the file. Once in the new location, I hope I don't need to resize it as each has its own rules.

Perhaps it's a faulty memory, but I recall that ctrl-c, ctrl-v, and ctrl-x was all I ever needed to know.

Is there some way to help me understand/learn this? Perhaps a chart that shows when to use each command? Apple led the way in the 80's by simplifying commands and creating standards to be used. To me, learning this is the equivalent of learning how to walk. We take thousands of steps each day tgo help us do anything and never need to think about it.

Am I looking for the Unified Field Theory, or hunting for a Unicorn? Am this some sort of lawless zone? Is there a simple chart that can help me understand which options work and when? Or am I looking for one way to pronounce "ough"?