Hi! You've done a good job digging up secrets it seems :) All I'm going to say is that the audio recording you described in 2. is the key to finding the secret.
Hi again! Thanks for advice for secret, but I cant still solve it :/ After making some changes of speed and reversing some words in this audio on Audacity I could only hear: "Junior club, hi, you serious/ useries, input, rise, four, (?), suck" and then I was wondering if you have any group where I can solve this with others ( because I dont want immediately full answer). It would be great if you could invite me or some other people who play this game too! Im still in work with this puzzle and for any hints I will be grateful!
Edit: I also found where to put a secret code!
Hi! You're making progress. Nice. Now all you need to do is figure out the code. I'm not sure about any groups. Maybe some people here could help? Or you could try the steam community page for the game: https://steamcommunity.com/app/1046820/discussions/