I see, we still don't know what is the best choice in Nameless event too. And I think Hyao add this feature in order to make this game more serious and surprise players by show us that there someone who can withstand the power of save-load lol
But in practically, you can change your choice if you have a previous 'persistent file', one before you choose a choice with Nameless.
Persistent file is a file which contain all game data in there, a dialogue you have been read, a choice you chosen, and yes, persistent file contain a choice you chosen in Nameless event too.
In PC version, persistent file will be in 2 folder one in save folder which locate in game folder and another one in %appdata%>renpy>lustfuldesire ..
I'm not sure that we can use a same way in Mobile version, but in PC version you can replace old persistent file to current persistent file in both folder to remove a choice you have been choose. BTW you may have some risk with this because persistent file is very important file for a game, it may cause some bugs if you replace or remove it so please consider it with care.
Like I have said, I don't know about Mobile version because I don't play on that platform but I'm sure there someone who play in that platform who can help you. But I'm not really sure who they are.
