Multiple issues

[serg]

At least here the filter is properly used.
Can't really do anything if the filter isn't effective with a specific source.

Whatever parameters/combinations I've tried on different videos - no effect.

Using something like:

DeSpot(median=false,seg=0,mwidth=1,mheight=100,interlaced=false)

should definitely show some effects.
https://avisynth.org.ru/despot/despot.html might help with configuring the filter.

Cu Selur

Never mind, so far Didée's despot works for me.
What filter would you suggest to remove tiny vertical lines (you can see them in the both my sample videos)?
Whatever I've tried (including DeScratch) - no luck so far.