Librem13v2 screen still flickers after applying workaround

Has anyone found a solution to screen flickering on the Librem13?

I have applied the enable_psr=0 workaround that was suggested in an old thread and confirmed with systool.

$ sudo systool -m i915 -av | grep psr
enable_psr = “0”

The other suggested workaround, enable_rc6=0, has no effect because enable_rc6 was disabled since kernel 4.16; I am running 4.18.0-2.

The flickering is more than just an annoyance. It is so bad that web pages with dark backgrounds are unreadable and give me a headache.

Is there a way to stop the screen flickering?