You should consider when it comes to LQ version to actually try for WebP format with 95% quality ratio... the difference is negligible when it comes to quality but the benefit of the size reduction is pretty good. IIRC sometimes the images are even bigger then the original when going 100%.
Anyway, since i'm kinda low on space i had to repack some stuff out of necessity but wanted to keep the quality high yet have significant size reduction... what i concluded is that WebP format is the best for this and going beyond 95% QR is not worth it when it comes to size and going below 75% QR is not worth it when it comes to quality.
What i want to say is... big respect for devs that actually optimize their EGame, it is appreciated.