You're very welcome, and thanks for the additional comment. I have a low spec machine, running Linux and using Firefox as the browser. Dated NVDIA GPU (like probably the better part of 10 years old). Screen resolution 1024 x 768 (low res by modern standards). I believe that I do not have video hardware acceleration enabled due to videocard driver limitations / not installed. Possibly, WebGL is being rendered in software instead of hardware, which would certainly explain a lot for why the framerate is slow and laggy. However, I also can play videos in the browser and most 2D games without any lag issues. Some 3D games seem to work, with mixed results.
I hope this information is helpful for you. Linux does have decent NVDIA drivers that make use of the videocard's GPU capabilities, so the lack of hardware acceleration is not always an issue for computers running Linux OS. I should really probably upgrade my system one of these days! But, it's fun to try out games on lower spec hardware too, such as older laptops etc.. I heard that Defold is a really efficient game engine, that runs games well even on older hardware. I personally have never used Defold and have been using AppGameKit for now, but at some point I may try it and see what its results are like. I hope you continue development of your game, it's really unique and it has character!