Finding a memory address in a game?

Question

C++ / C#

How do the creators of unofficial multiplayers for games (Take an example like GTA V, but in general Rust is also possible) look for addresses in memory that execute some kind of process? How to change HP and give money is easy, through sifting values. And here is how, for example, to catch the fact that a player hit someone, got into a car, or how to disable NPCs in the city, checkpoints, actor spawn, the state of the doors in the car. Moreover, it is much more interesting how to find data in the game's memory about the server GUI. This will not pass through the sifting of values, the same NPCs are 0/1, and 0/1 can belong to many things.

Preferably with ++, if it is needed here at all.
I assume that we should think in the direction of the debugger, but I'm not sure.

Answer 1

And here the search for memory addresses?
If you have used cheatengine or Artmoney exclusively by searching by value, and you have no idea how programs are written and what programming languages ​​are, then yes, it's about debuggers.
A debugger is taken, the code is decompiled, replaced with its own, when it becomes clear how to replace it.
Yes, you need the skills of a good developer, with experience in reverse engineering, and not just one, such things in the absence of source code is a lot of man-hours of some commune, rarely a loner.