It's okay. I think the lighting is just a me thing. I am on the spectrum so muted colors naturally jar me, especially if they are dark (Mauve, and Peuce are my least favorite colors funnily enough). It's kind of why I usually can't sit through most horror games on 3D engines funnily enough.
But yeah I even joked with someone your game updated my graphics card on the computer I inherited from my Dad (he had it since 2013).
A voice cue could work wonders but I worry it might feel kiddish doing that since I only heard it in Sonic the Hedgehog games. It might be the only choice I guess. Your voice naturally was nice to listen to before getting into a stealth mechanic like that.
Also, I gotta be honest the jump from RPGMaker to Unreal was pretty big for you. I kind of have that anxiety if I decide to jump from RPGMaker to RenPy as I still haven't quite mastered eventing in the former. But that jump makes me happy for you as well. You seem to have a strong grasp on it and I hope it helps you improve on other engines as well!