On my previous vehicles I simply added this many point sources,
The main problem with that is that people who have their settings for light sources set to a low number will only see a few of those and it'll look bad.
But if I give invisible bar lights (one for each department) with varying intensitiy (according to the number of sections ON), the zig-zag pattern is lost (though not like it was visible really in LOTUS).
I would suggest using that for everyone who doesn't have detail light sources activated if the difference isn't that big, and use detail light sources for the point sources for everyone who does have those activated, because those aren't limited by the settings as far as I know.
Should I use this very basic lighting with maybe some effect on the ceiling texture (like in OMSI with the baked lights)?
I don't know if there are any plans on Lotus' side to change light effects, but I would recommend using that (for example by using a lightmap for the celing with the rings of light thrown by the lamps on it), although you will probably have to experiment a lot until it'll look good. Maybe I'm unaware of some feature which would make this easier, though.