Okey I looked it up and had to realize that PowerShell does not have true color support, according to this open discussion github.com/PowerShell/PowerShell/issues/2381 The reason why I chose PowerShell is that I had problems using OmnirSharp with vim on WSL2. So eithter I solve these problems oder the color ones. Thank you anyway

When I do this I lose all the colors (everyhting becomes to the color which I have i the corresponding terminal)

@D.BenKnoble Thank you for your fast answer. As you can see in the picture now it is more than a little bit off (if you know gruvbox colors). I used the gruvbox plugin with Vim 8 within WSL2 in OpenSUSE and Windows Terminal as well and the colors were represented correctly.