Stop my screen auto dimming

i have a few Apple products that are automatically dimming there screens all the time even when there fully charged I’ve been in my settings and everything is set not to dim at anytime but they still keep dimming on there own , all my products are fully upto date on there software even my iPhone 11 Pro is doing the same I’ve got everything set as family sharing, I thought it cud be that at first but I’ve removed that and wiped all my products back to factory settings but still no change someone please help