Hi, this is an unfortunate reality of Godot web exports as there are forced to be single threaded. I'm very sorry to hear that you're not able to run it. I did find I had slightly worse problem with audio on Chrome and it was better on Firefox, so maybe another browser might help.
The only other suggestion I can possibly suggest is using the Itch App to download and install the game which might also help with performance. I totally understand if you're not able to willing to do this though.