Input Lag On Monitor Question

[Cryogenetic]

Bit of background I used to own a BenQ XL2411Z but after many years of excessive gameplay it stopped working, so I went with the AOC G2590FX to replace it. I did a lot of research and the monitors are supposed to have the same input lag (4ms) but I've been feeling a lot more on this monitor than the BenQ.

Something I've noticed is that there is no way to disable freesync on the monitor itself. If it's enabled in Nvidia Control Panel then the settings indicate freesync is being used as the vertical frequency. I can use nvidia profile inspector to change the behavior to fixed refresh and it indicates in the settings that the vertical frequency is now 144, however I've been told not to use fixed refresh, and to use G-Sync Forced Off instead, but when I do that the settings indicate Freesync is still the vertical frequency.

Another weird thing is the monitor has a low input lag mode that is greyed out when the vertical frequency is freesync, but can be turned on and off when the vertical frequency is 144.

What I'm wanting to do, is try to figure out why this monitor's input lag feels higher than the BenQ when playing uncapped FPS games at 300+ frames like CSGO, is it because of this freesync weirdness? If so I could just disable it at the driver level but was hoping to keep it enabled and just turn it off at a game by game basis for CSGO or Valorant.

I currently have overdrive set to medium, on my benQ my AMA was set to high so I feel like that should be comparable (which from what I understand only has an impact on blur not input lag anyway) and there is nothing else on this monitor that seems to be tied to input lag other than low input mode. Was I simply just scammed by the reviews or have I got something set wrong? Thank you for any help.

[pwn]

connection interface? on 2411 and 2590

[Cryogenetic]

On the BenQ I was using an active (through USB) female DVI-D to Male DP adapter because my GPU only had DP and the 2411 would only reach 144hz through DVI-D. The 2590 is using a DP 1.2 cable, and I've tried multiple different cables (4-5 as of right now).

[TN_fun]

Monitors themselves differ in input lag. There are many reasons for this. Firstly, there are different panel, different scalers. Active freesync can also give a slightly larger input lag (on some models, where it is possible to turn it off in the monitor menu, I saw it on the asus) But input lag nothe is too big, you can live with it. But you can still feel it if you are sensitive and have something to compare with.
You do not have an option in monitor to turn off freesync and since it annoys you, just get another model by selling this one. Get 2411p or 2411k again (that's much better p)