I was in old tbilisi and saw that narikala is under renovation,what are they even renovating? If its still left as ruins of fortress it was,what are they even renovating if theyre not rebuilding an fortress it was?

They are consolidating the Walls and reinforcing them. Narikala is actually endangered by earthquakes and this renovation is helping stabilize it. They are also adding new paths and decorative lights. Also removing some debris and fixing up some broken parts of the walls.
The renovation is expected to be finished in August. 🙂