Yes, there are some issues when exporting to HTML in Godot. But if you know them and keep them in mind while creating and exporting the game, it’s not that bad.
One thing I noticed is, that the threading api doesn’t work with html5 export. But you can work around this most of the time. And I guess most games don’t even use it. It’s mostly handy if you need to load a lot of stuff in the background.
The most important thing is to GLES2 (in the top right corner). This will improve the compatibility with different browsers.
I created a ‘game’ to test the performance and compatibility of godots html5 export here: https://redoxgames.itch.io/endless-offroad-driving
From the feedback and my experience it works good on: Firefox (Windows/Linux), Edge (Windows) And it doesn’t work on: Chrome running on Chromebooks? (Maybe these ‘Chromebooks’ where just underpowered for the 3d game?)
If you play the game, maybe you can leave a comment on your system and if it is working.