Does someone else have the issue that sunrise and sunset is wrong. They are switched and the time is wrong. I own the fenix 5 (non saphiere, FW 2.40). I'm using the 24 hour setting with UTC +1 (Germany, Berlin) at the moment.
I had this problem when I first set the watch up. It was fixed by using GPS for the first time on the watch. So try, for example, going to Menu > Clock > Sync with GPS.
I guess this tells the watch where it is in the world, so it can use the correct sunrise/sunset data. (It didn't seem to be enough to have GPS enabled on the connected phone.)