a lot of things go in to the speed differences. I don't understand a lot of the more technical mumbo jumbo but know enough to get the gist.
Hardware is part of it. Even a cheap gaming computer will have more power than the best console game. the refresh rate is only a small part of the equation, plenty of PC monitors cap out at 60hrtz too. how fast the hardware is able to render and react to inputs is separate than just the refresh rate you see on your screen. also mouse and keyboard tend to be wired, which is going to be faster, and have better response times over a bluetooth wireless connection. also less chances of faults. also the PC itself is typically more likely to be hardwired to the router, while most consoles just use WiFi. again a slightly slower and less reliable option for high end output/input, its a problem both ways.
its also easier to adjust mouse & keyboard, and generally the game in general to match your specs on a PC over a console. Games have to be "dumbed down" to run on a console, while you can tinker to your hearts desire with all the PC settings. that dumbing down means you aren't going to have personal adjustments that would help your performance. A lot of times this means a PC player "sees" more than what the console version renders. this can help in some cases, but it can also lead to the PC player thinking they are hiding when they actually aren't vs the dumbed down console version of the game.
being able to more accurately place a mouse "cursor" vs a console "cursor" is typically complete bs. the targeting reticles are the same on both PC & console. its the tuning of the mouse and keyboard that give more control, but you still have to be "better" to get the actual use. being on PC doesn't make a "6" skill PC gamer any better than a "6" skill console player. but what happens is a "10" console gamer could be capped by whatever performance is set by the console, whether thats a "6" "8" or whatever, and the PC gamer doesn't have that same artificial cap.
if you are playing a cross console game you are going to have to play on a server that can handle whatever the highest input is, typically a PC. the consoles connecting to said PC server have a little extra "translation". the same issue exists in reverse if a game starts on console and eventually comes to PC, the PC is forced to play on console servers and there will be lag there. but since all games are developed ON a pc its much more likely for it be servers designed for PC input over servers designed for console input.
there is also the very strong need to just git gud. if someone is gaming on a PC they are probably more into it than someone who just has a console.
