"HTML still not working :("
What game engine are you using?I know for Godot 4 games to work on the web the checkbox "SharedArrayBuffer support" has to be enabled. Not sure about other engines but you could ask on the forums.
Hmmmm...I've opened the file in Firefox and I get a network error. From what I've seen on google and my general knowlege of Godot 3, I assume it's a bug with v3.3 because I first used 3.5 and HTML worked fine. Try exporting in 3.5 or 3.6 (the godot file should still work with later versions of godot 3) and see if that changes anything.