I am not a Unity guy... but I've more than 7 years in Web game development and recently it came to my attention the really odd and confusing way unity handles brotli and gzip compressions by default.
I had to write give it a piece of my mind to the internet
So, here it is, a post explaining how web compression works and how to properly compress your WebGL build
Milton’s Blog
If you ever exported and tried to publish a WebGL game made with Unity, you were probably bombarded with really confusing settings and some esoteric configurations in your server. Let’s explore how stuff really should be done