• Update your GPU drivers https://www.howtogeek.com/135976/how-to-update-your-graphics-drivers-for-maximum-gaming-performance/
• Install Direct X (even if it's already installed) https://www.microsoft.com/en-us/download/details.aspx?id=35
  Now restart your PC and try to start the launcher/your game again.

If the issue persists then your PC probably doesn't have a Direct X 11 capable GPU but there is a way to bypass that.

• Download and run DXCpl.exe https://drive.google.com/file/d/1qvWbHrnBVVibYozaO9peXcSS9ovEBMhd/view
• Click "Edit List..."
• Click the three dots right of the "enter a process or folder name" field and select "plutonium-launcher-win32.exe" located in C:\Users\Username\AppData\Local\Plutonium\bin (Username is your Windows username)
• Tick the "force warp" checkbox and select "11_0" from the "feature level limit" dropdown menu
• Hit OK & try to start the launcher/your game again.