S2421HGF, ghosting when G-Sync is off

Hey,

I bought the Dell S2421HGF 2 years ago and I've had this issue with ghosting back then. However, I managed to resolve it in a weird way basically by turning on G-Sync and then taking the DP cable off the S2421HGF, waiting around 10 seconds and then putting the cable back and finally turning G-Sync back off. That removed all ghosting for me.

I used to have a GTX 1050 Ti back then. I just installed a new RTX 3060. For some reason this solution that used to work for me does not work anymore and I only don't have ghosting when G-Sync is on? Why? How does G-Sync remove the ghosting issues for me? I try the solution that I used to do but it doesn't work. The ghosting comes back and it only goes away when G-Sync is on.

Any help? Thanks!