A great thing about performance and SEO falls into this bucket, and security too, is its ongoing. You're never done, it's never a set it and forget it, you're scoring all hundreds. You could score hundreds across speed tests, and come back a few months later and be scoring terribly. You always have to monitor it, and take action and steps to keep your performance in check. Because it does over time get worse, for whatever various reasons.
https://dothewoo.io/knowing-what-your-sites-performance-means/
https://dothewoo.io/knowing-what-your-sites-performance-means/