Soooo. I tried the same and sound is working out of the box.
Wifi is working well on battery so far
I have no idea what problems my first copy has, but it seems to not a general problem with the image.
I have now found a lead why there was no sound. With the original manjaro user sound works. I have then created a new user and added it to the same groups as manjaro and sound does not work anymore. I have to look into that a bit more…