Thanks for reporting this. I'm trying to figure out why this error would be happening for you and no one else.
I'm curious what Browser (and version) you happen to be using? I can see some reports from January that apparently Firefox version 134 had some issue that caused Godot web games to fail to find their .pck file (where the game data lives) and so they get that error. And people report the issue going away with version 134.0.2. So perhaps check for a browser update if your version is somewhat old, or try another browser (assuming you feel motivated enough, I won't blame ya if that's a hoop you don't feel like jumping through).
If it's not that, *maybe* it's some issue with some browser setting, assuming you're the type of person to get into very specifically configuring your browser. They can have some affect on Godot's file functionalities; notably there is a feature that requires the browser have IndexedDB turned on. But I don't believe that functionality is used by my game. So this seems unlikely, but in the off-chance you are some browser configuration power-user, maybe something will jump out to you.
If neither of those are relevant to you, I could try uploading a downloadable version for you to try, and just take the bet that you're unlikely to *also* have it happen locally.