I've made a lot of encoding with these settings for 1080p videos (i use AviSyhtn as decoder) :

NVEncC64.exe --vbrhq 5000 --codec h264 --preset quality --output-depth 10 --lookahead 32 --max-bitrate 0 --aq --aq-temporal --fullrange --bluray --vbr2 5000 -i "in.avs" -o "out.h265"

I get perfect picture without artifacts. Tested with about 30 encodings !!!

I can use these same settings with h265 i have to remove "--bluray" i get similar really good quality too !

I only have issues with some 4K videos. I only change bitrate from 5000 to 16000. Some are perfects, some videos give me artifacts wirh h265, but if i use h264 picture is perfect... I hope this will help others !!