Wifi calling is turned off as you can see.
This symbol is for VoLTE.
And where is the option to turn off on volte? Cos settings finds nothing 
Why would you like to switch it off? You can’t use your smartphone for telephone calls in areas without 2G/3G afterwards.
Not necessarily but I don’t like that the icon wasn’t there before and is now. Did I not have that option before? Also, if like to find a way to turn it off just to see if the icon goes away. Even if I would turn it back on later. But nothing comes up with search: voice over; volte, voice (this one only has lots of voice command stuff)
You can’t just disable the icon without disabling the function. It depends on your provider if it is possible at all but if it is, you can find it in the network and internet settings-> SIM cards.