In-game Resolution: 4K, while my monitor is 1080p Direct 12: On DXR: On Ray-Tracing: Ultra DLSS: On Almost all the settings are at their highest, except these two: "Special Effect Quality" & "Special Effect Amount" are set to "High", not "Ultra", cuz it may crash frequently on "Ultra" once a big explosion occured nearby (e.g: V1 rocket or big tank shell), or a plane flying too fast through nearby, probably due to my poor Motherboard and Memory Generation is DDR3, not DDR4, if it's not the problem of game itself.
Update: The "Post-Effect Quality" has been reduced to "High", rather than "Ultra", due to crash, and I doubt it maybe caused by "Ultra" Post-Effect Quality.