Thermostat issues February 2021

Yesterday I woke up to thermostat blowing cold air and stuck at one temperature. I reset the thermostat using the wall unit and then removed it from my app and added again. It fixed it.
I also saw that now I lost one function in the app that allowed to me to choose between fan being on, or cycle or off.

Day later the thermostat is stuck at blowing the temperature and at one minute the temperature difference is about 5 degrees Fahrenheit. Is that the sensor that’s messed up?
Also the option selection is “heat” yet when I chose different temperatures there was something called “safety delay 1 min” before it would turn on the fan. With heat on the cold air should not be on. What is going on.

Help :cry: