I’m not as familiar with wu-wei. The way I understand Mushin no shin is that there is a variety of ways to achieve it, for me it usually requires physical exertion but others are able to through meditation.
The important bit is the peace of mind. You can apply Mushin no shin to all areas of life but I confess that I’m nowhere even close to silencing my inner voice and always being present!
I hope that helps and have a wonderful day!