Can you post some screenshots? I've tried turning shadows off, and saw no difference. I just use reshade to pump up gamma and, also eye adaptation effect. It makes almost all routes playable at night when summer/clear is selected. Also I've tried the latest german route, and it's playable at night without any tweaking, so I guess they must've fixed some ligting issues, and I expect all new routes to come will be playable at night. Existing ones will probably remain as they are, though.