Hi! I'm super late to this, but if you are still unable to play because it says somthing about " linux-x86_84" or something such as that, the files are in fact in the game, and I know a shortcut using the steps from the post! All you gotta do is to steps A thru E as usual first. Then, you gotta go to your files and open up DDLC thru your Linux files. Next, open the "lib" file and find the subfile "linux-x86_64". double click it and select "open with terminal". Once the terminal opens, just follow steps L to P! It will open the same way as it would if you followed the original steps. :)
Yep, I'm still here! To be completely honest, I don't really know much about Linux and coding stuff, and I don't even know how I figured that out back then(；^ω^) but it was what worked for me. I think I have time sometime today to jump back into it. Maybe we can figure out a solution for you, too!