Im printing on my k1. Have been tuning a lot today. Steppers, bed, temp, speed, acceleration and jerk, pressure advance, flow, cooling and retraction. It seems quite good. It's still stringing a bit. But the issue i have is the z seam on the inside on the circular part.The z seam on the outside isn't over or under extruded, it seems to be spot on. But the seam on the inside seems to be under extruded. Any tips on how to solve this?

This part was a test part. The part i want to print is a cylinder, so that will have the same issue.

Material: PET Temp: 215°C Speed: 125 mm/s Acceleration: 8000 mm/s Jerk: 7 mm/s PA: 0.066 Flow: 97% Cooling fan: 40% Retraction length: 0.6 mm Retraction speed: 50 mm/s