Newly tuned WRX-STI 04 rally build feels unstable on dirt

I recently begin to figure out a rally tune for my WRX-STI 04. After finishing a base tune, I did manage to make the car feeling smooth in the corner.
However, the car feels unstable on the dirt/water surface, and I’m pretty sure it didn’t bottom out. For I solely focus on cockpit view drive, the car feels too sensitive to the surface change.
For I’m quite new to tuning area, what should I begin to look to solve the problem? I’d be more than grateful to hear any advice.

I think that fh5 is more sensitive to the surface change.

Have you had any luck with the tune? When you say it’s unstable I’m thinking that the car is bouncing around too much, correct me if I’m wrong. I would make sure you don’t have too much camber and then start adjusting the rebound stiffness. Lowering the rebound will make the car more “floaty” over rough surfaces. Same goes for the bound tuning but typically the stock tune has rebound a bit too high.