Your set up sounds fine. The lack of eating sounds like a seasonal issue to me.

Some rosys prefer small prey items / find them much harder to resist. Try offering him a crawler or small hopper as a meal.

If he refuses this, and he looks like he has a healthy body weight etc. you may just want to turn off the heat and put him somewhere cool and let him sleep through the winter.

Some of my rosys have started to slow down and stop eating too.

-Alice