This video is misleading. Not everything in RDR2 has this slow of input lag.
It is only comparing 1 thing in the video, flicking the left stick > character moving to reflect it
Don't get me wrong, that is BAD, and I am in no way defending input lag. I am merely pointing out that this video is misleading.
That action in RDR2 has absurdly high input lag compared to everything else.
For example, when you aim your gun, and press the trigger to shoot, the input lag is the same as any other 30fps shooter, as is the aiming response.
This video is literally cherry picking ONE action in this game that was, for some unknown reason, programmed to have higher input lag than anything else.
There are other actions in the game that are programmed to have higher input lag - however for a reason - because the buttons serve as 2 functions, a tap and a hold.
L1 is the button you use to holster/unholster your gun, however is also the button you hold to bring up your weapon wheel.
There is a large amount of input lag from when you hold down L1 to bring up the wheel, to it actually showing up on screen.
This was intentional, as a cushion so that way there's no confusion between the two actions.
Same thing with the R3 button. Click for dead-eye, hold to look behind character. There's a lot of lag when you hold it down, so that way the game recognizes that's what you actually wanted to do.