Hello
I just replaced an old water softener yesterday with new GE 30,000 grain model.
Even a day later now, all the faucets and showers have less hot temperature. I have to turn the knob hotter than normal, and even at the hottest, it does not scald like it did before.

I did not shut off the water heater or turn the setting down. If someone has an answer for this, I would greatly appreciate it.

Thank you.

Hot water starts at the water heater. Go to the heater and make sure the thermostat is set to 125 F. Also, if you have hot water circulation pump, bleed the loop.

There is a chance the temp is the same but the volume has dropped on the hot side so you are getting a bit more cold mixed in. Do what Milo wsays and actually test the water temp right out of the drain spigot, good time to flush the heater too. What temp do you get