I'm trying to configure AWS storage in generation settings (Storage) but it doesn't seem to work with either of the modes provided, could somebody assist me with it ?

I have tried all combination of default storage engine as S3, S3V4, S3V4Alt but always getting error 500 on uploads. Attached is the image of my settings page , check if anyone finds something obvious which i'm missing.

Can somebody explain what is significant of these storage engine type ? or my previous platform all i had to provide was AWS Key & access key n it worked flawless

How does it links to Signature version from engine type version ? this has taken a lot of time then i expected but still unresolved.