Correct ideas, wrong understanding.

The server executes stuff at the beginning of a tick. A tick happens on a perfect server every 50ms (since a perfect server is 20tps, which is 20 ticks per second).

All packets get executed in order received at the beginning of each tick (but they all typically get exceuted under 1 ms, which means it looks like they happen at the same time).

Example 1 -
Counter = 40/50
Tick 1 is 40/50ms in. You have 8ms ping. You send an attack packet The server will receive the at 48/50, which means the server will execute your packet in 2 more ms, or at 50. If you had 12 ping, the server would receive it at 52/100, which means it would execute at counter = 100. Ping still matters, but not as fast as you think.

Example 2 -
Counter = 2/50
Player 1 has 5ms ping
Player 2 has 40ms ping
Player one and player two sends attack packet at 2/50. The server receives them at 7/50 and 42/50 respectively, meaning they both get executed within nanoseconds of each other at 50ms. This case ping does not matter for this particular packet.

Hope this makes you understand it better.

Pretty much, unless you have 75+, you're packets will typically only be received by the server 0.05 seconds apart. Ping matters, but not as much as people think it does.

and a tl;dr

I want kevstah ping doe