Finally tried this recommendation and it worked wonderfully.
Definitively better performance with DX12 it seems, and clarity too.
Need powerful gear to push this but the quality is excellent.
To answer my own question above, it does work the same with Rise of the TR. Though shadows seem to become quite offset in that one.
DX12 mode seems to cap at 60fps even you force it off via Nvidia Control panel. Chime in if you know how to bypass this.