First, screen shots are good, but more info is needed. Like from your 'dxdiag'. We need to what kind of potato you have running directx11. In particular, the System and Display tabs will be a big help.
Additionally, turn off full screen. Being "Windowed" should help performance. You might also search the forum. IIRC, there may be an command line option/switch to force a particular DirectX version -- if that is any help.
Be aware, it's likely the potato may not be able to run this. Although WDC a moderately light Unity game, it's not a Ren'Py VN, RPG Maker, Godot, or other light engine by any stretch. It does require some basic 3D support.