Good question, the key difference between the two versions is that one uses DX11 and the other uses DX12.
The DX12 offers better visual quality since it supports the latest features in Unreal Engine— so if your system can handle it, that’s the one I recommend for the best experience.
The DX11 is meant for players with older GPUs. It’s basically a fallback option, though I can’t guarantee every feature will behave exactly the same, since DX11 is a bit of a downgrade in terms of engine capabilities.
That said, both versions share the same gameplay and content.