In an attempt to be helpful (although it may sound as if I'm being overly harsh), allow me to state that there is no excuse for these renders to be such poor quality. It's as if we've travelled back to 2015 or so.
First, produce the CG at full quality, uncompressed. If you want to spit them out in png then do it, but do it without nuking the things. Get rid of all the noise, especially in low-light situations. Once you have them rendered use XnConvert to flip the PNG files to webp. Your pics, some of which are really ugly, are currently ~2+ MB large which is totally unnecessary. Convert the output to about 80% quality and you will have a great pic at 200-500K. You'll save file size and have better quality...a win-win. I would advise you to look at other games. Virtually no one is using PNG any longer. If you need some help with this process just send me a note and I'll walk you through it. But whatever you do, get rid of all that noise.