Once you click it its gonna black out your screen for a few seconds dont worry about it its normal its just restarting your graphics driver you need to do this in order to see the 75hz option on the nvidia panel.
Once its done its goint to promp this little thingy. just click exit lol
fenxm
Just found out the solution my guy.
Instead of using Nvidia control panel for overclocking your monitor you need to use CRU(Custom Resolution Utility)
https://www.monitortests.com/forum/Thread-Custom-Resolution-Utility-CRU
Click "Download: cru-1.4.1.zip"
[Make sure you deleted your overclocked profiles from Nvidia ALL OF THEM]
https://prnt.sc/ov0qkq
Extrack the zip file on a folder and then open "CRU"
https://prnt.sc/ov0r0y
In the top left corner the model of your monitor should be displayed with an (Active) thingy near to it
Make sure it says active dude
https://prnt.sc/ov0rj6
then just click on add
https://prnt.sc/ov0rrx
Once you click add make sure that "timing" is on Manual and just change the refresh rate in the litlle box below dude. then press ok.
https://prnt.sc/ov0t3d
Once all of that is done just exit out of the program clicking on the "ok" button
https://prnt.sc/ov0tsu
Now go back to the folder where you extracted CRU and click on "restart" if you have 32bits O.S or "restart64" if you have a 64bit O.S
https://prnt.sc/ov0ud7
Once you click it its gonna black out your screen for a few seconds dont worry about it its normal its just restarting your graphics driver you need to do this in order to see the 75hz option on the nvidia panel.
Once its done its goint to promp this little thingy. just click exit lol
https://prnt.sc/ov0vt5
then go to your nvidia control panel and there it is my guy! 75hz!
https://prnt.sc/ov0wtm
Now for the real test... just go to minecraft and boom! magic!
https://prnt.sc/ov0xpu