Godot 4.0 broke web exports without a webpage having certain headers(over my head content), but sites like itch have those things. I believe the explanation was because of having mulit-threaded support in the engine.
I have held off upgrading from 3.5 because my games I publish on my simple github page and that change on 4.0 would not work on my github page.
There was rumor of providing a single threaded web mode in future releases(4.1 was mentioned), but don’t know if this happened. I check release notes every few months but haven’t seen if this change has been made.
Are web exports fixed for godot now?
As an addendum, for those who know that they’re going to export their game to a Godot-ready server, but want to test locally, I suggest the “Remote Debug” button right next to the stop button, after exporting. It looks like a computer monitor but all Apple-logo’d up, if you know what I mean. One of the options is “Run in Browser”, which works pretty consistently; after running it once, it apparently keeps a local HTTP server up and running too, as the “Stop HTTP Server” option appears.
I don’t honestly know exactly what it’s doing differently yet, but this is a great way to test out browser performance for a game before going live with it.