I'm glad you enjoyed my PC Report as it was first I even wrote and thanks for interesting information about game's behavior. I have also tried understanding the game's encrypted files, a result of which you can find
here - sadly, with the exception of like 2 maybe 3 options, it's pretty much all that's available in game's options. However, some interesting stuff can be found when playing with a console. Since the console cvar completion when pressing a key, here's some notes:
getv variable_name - returns a variable value
setv variable_name value - sets the value
Variable names can be checked using: listv. And if I understand it correctly - cvars can be checked using listc. Despite like going through all of the variables and commands, I wasn't really able to come up with anything that'd make graphics much better, aside from increasing shadow distance (I think it was variable starting with r_ and had CSM in it)