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Can anyone help me with this theory about microprocessor, cpu and computers in general?

( I used to love programming when during school days when it was just basic searching/sorting and oop. Even in college , when it advanced to language details , compilers and data structures, i was fine. But subjects like coa and microprocessors, which kind of explains the working of hardware behind the brain that is a computer is so difficult to understand for me 😭😭😭)

How a computer works? All i knew was that when a bulb gets connected to a battery via wires, some metal inside it starts glowing and we see light. No magics involved till now.

Then came the von Neumann architecture which says a computer consists of 4 things : i/o devices, system bus ,memory and cpu. I/0 and memory interact with system bus, which is controlled by cpu . Thus cpu controls everything and that's how computer works.

Wait, what?
Let's take an easy example of calc. i pressed 1+2= on keyboard, it showed me '1+2=' and then '3'. How the hell that hapenned ?

Then some video told me this : every key in your keyboard is connected to a multiplexer which gives a special "code" to the processer regarding the key press.
The "control unit" of cpu commands the ram to store every character until '=' is pressed (which is a kind of interrupt telling the cpu to start processing) . RAM is simply a bunch of storage circuits (which can store some 1s) along with another bunch of circuits which can retrieve these data.

Up till now, the control unit knows that memory has (for eg):
Value 1 stored as 0001 at some address 34A
Value + stored as 11001101 at some address 34B
Value 2 stored as 0010 at some Address 23B

On recieving code for '=' press, the "control unit" commands the "alu" unit of cpu to fectch data from memory , understand it and calculate the result(i e the "fetch, decode and execute" cycle)

Alu fetches the "codes" from the memory, which translates to ADD 34A,23B i.e add the data stored at addresses 34a , 23b. The alu retrieves values present at given addresses, passes them through its adder circuit and puts the result at some new address 21H.

The control unit then fetches this result from new address and via, system busses, sends this new value to display's memory loaded at some memory port 4044.
The display picks it up and instantly shows it.

My problems:
1. Is this all correct? Does this only happens?

2. Please expand this more.
How is this system bus, alu, cpu , working?
What are the registers, accumulators , flip flops in the memory?
What are the machine cycles?
What are instructions cycles , opcodes, instruction codes ?
Where does assembly language comes in?
How does cpu manipulates memory?
This data bus , control bus, what are they?
I have come across so many weird words i dont understand dma, interrupts , memory mapped i/o devices, etc. Somebody please explain.

Ps : am learning about the fucking 8085 microprocessor in class and i can't even relate to basic computer architecture. I had flunked the coa paper which i now realise why, coz its so confusing. :'''(