every one of your obervations was correct (btw I got to know the tabula recta as vigenere square [1])
kcovjgfktgevgf was the key for noqinylndnqysmwfacvjrrfj\n (and \n is indeed endoftheline)
I used an online vigenere chiffre "applet" (ok it is javascript so not really an applet but who cares) and I got an off by one (just define the alphabet as bcdefghijklmnopqrstuvwxyza or use jbnuifejsfdufe as the key)
PS. Without tor you can use [3] and thx for making me waste that 5 minutes :D it was fun
Don't know it isn't my puzzle. Maybe I'm wrong and this isn't the solution and there is still some way to go.
Edit: damn wanted to try the /999 but the site is down (yeah I'm using tor and not the onion.link link) I hope this is just the HN effect and it will soon work again
Edit2: I hoped to find something hidden in the image itself but it wasn't
Edit3: If anyone else wants to give it a shot https://blacklotus.github.io/ uploaded the index.html and vigenere.png (oviously no other files)
- The "vbizukfplsqf...." is not part of the puzzle
- The original website is available at https://vbizukfplsqfdhbr.onion/
- The page title is "Caesar Was Rome's 2nd Emperor", hinting to Caesar cipher
- In a HTML comment: "kcovjgfktgevgf" which is "I am the directed" encrypted via Caesar cipher
- In a HTML comment: "6e6f71696e796c6e646e7179736d77666163766a7272666a0a" which is the hexadecimal for "noqinylndnqysmwfacvjrrfj\n"
- The image is named "vigenere.png", hinting to Vigenere cipher