Finally received the 'Barmaglot alieexpress adapter'. I was a bit affraid the combination wouldn't fit in my Olympus M 5 III but it does. The trick was to connect the cables first before sliding the camera in. It helps that the adapter is extremely flexibel. So flexibel, that I am happy that I also ordered a spare.
Anyhow, the weakest point of my small camera, the battery, does not bother me any more.