In the future, please keep all DLC related questions to the DLC Itch page; this comment section is mainly for the base game. You also don't need to censor the word NSFW here.
If you've correctly installed everything, you just need to start a brand new game and enable the DLC. Also, make sure "streamer mode" is disabled. There should be no problems after that.
But if the DLC isn't working with the newer/freshly downloaded version, check that the DLC folder name is correct (i.e. it shouldn't be "14nightswithyou-paid"). If it's still not working, please visit the DLC's Itch page and leave a screenshot of what the DLC looks like inside the "game" folder, and I can try to help further.