I have tried reinstalling the app and I am still not able to turn on the slider. Furthermore I have tried logging into my sons phone with my account and the slider turns on. I had my son login to my phone with his account and the slider works for him.
It seem to be an issue with my account on my Phone.
We both have the same iPhone 12.
I have contacted Apple and they have advised me to restore my phone. I am waiting to see what the community has to say before doing that.