@Arco123 Thanks for your help.
Indeed Scatterer and AVP both have atmo configs (which differ slightly on a few parameters).
Not sure how KSP handles such doubles, but it seems the AVP config has a line at the top that checks if an atmo is loaded already (?)
!Atmo:HAS[#name[Kerbin]]{}
(Also AVP's config doesn't properly close all its curly brackets, but thats something for another thread I suppose).
Anyway deleting either the AVP or Scatterer atmo.cfg does not make much visual difference for me, but deleting both does.
I guess this also removes any atmospheric effects on the rendered lights, but I much prefer this aesthetic.
I might try to approach this by tweaking the settings in the atmo config.