Your game seems to run smoothly in web. I always have some performance issues when I export my games as web.
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I had the same issue with gamemakers web export. It was really laggy and ran terribly. Godot web seems much better so far.
I'm new to godot so this could be wrong but, I think it runs smoothly bc I'm setting everything's physics process to false initially. Then I only enable objects that are inside the cameras view.