Start to Finish Cinematic Render Settings

Hello UE4 Community. I have watched countless number of videos online about all the possible settings to increase quality (lightmass settings / raytracing / r.SSR / r.temporalAA ) etc. as well as the post processing settings (screen percentage, etc.)

My question is, which values can be left default in the
-world settings
-project settings
-lightmass settings etc.

Should we enable Temporal AA, etc?

No one video addresses which options would be best from start to finish.
Also, is there a way to reset all settings to default values without starting a new project?

Thanks,
Andrew