Running UE5.3.2 on win11, Nvidia 4070 graphics card,
I had the same issue after updating my GPU Driver.
Checked the Nvidia control panel but found MFAA already off, after troubleshooting for quite a while I found out that the issue manifested because of my custom UE window loadout. After setting the layout to default all was resolved.
To anyone finding that turning MFAA off does not help; reset your window layout!