I used the slow preset because time wasn't really an issue, I encoded all of this to save space on my HDD while keeping that high quality fresh out of blender look. I will take a look at using the medium preset in the future but it comes with other changes that require more tweaking to get right. I choose the 10bit pixel format to eliminate banding and because x265 performs better with 10bit. I know there are some people out there who do like 8bit to 10bit color editing but that is not what I'm going for. As for the audio settings: it kinda doesn't really matter to me, I'm normally an audiophile but I don't care when it comes to audio in porn so I just choose half the bitrate of the original audio.
I sadly can't get you comparison frames because I already yeeted the original files to save space.
Also don't worry about complaining, I know that people in the encoding and video community have strong opinions and are often very toxic but I'm open to improvements.
EDIT:
I went ahead and updated my mega conversion script to extract frames at specific intervals, imgsli looks good but do you know of any non-interactive websites that I can use with an API?