Try for always from max-1 to -1 in loops and write things to be efficiently.
This may include using one larger function so you reuse variables sometimes.
Try to avoid remaking same values multiple times when you don't need to.
In general, yours is good and observe fast coding techniques also.
Well, topic is very old but I think it is very important for many individuals, including me and you. Optimizing website speed is very important for a better user experience and improving ranking in SERP (Search Engine Result Page). As you mentioned, you already use CDN, caching, and optimizing web hosting; therefore, it is a positive side for you. However, there are also other things that you can consider, which are listed below:
1. Compress images
2. Reduce HTTP requests
3. Lazy loading
4. Mobile optimization
5. Content prioritization
6. Use a fast DNS provider
Apart from this, I have also seen this post where author published a detailed article on it which you can read to get additional results.