I tried working with the solar power modify zone, tried to block full sunlight, but strangely, it didn't seem to work. I think I configured all necessary values:

Zone 1 ⤵

Zone Shape: Sphere
Zone Radius: 85 km (Planet is 70 km)
Affected Region: Surface
Soft Edge Factor: 0%
Enabled Type: Always

Zone Effect SolarPowerModify ⤵

Effect Strength: 0.0x
Effect Strength: 0.0x (I got this attribute twice)
Modify Type: Multiply
Threshold Min: 0%
Threshold Min: 100%

But the solar panels still receive 100% power. All dependencies are installed, no errors.