Hello @zap263
Yes, it may possible but you know it depends on the website and its code.
There are numerous things which Google Recommends to work for the optimization, and when we actually start working on it, we get some good results.
What we can expect is, best possible score without breaking the website functionality is good for us,
There are optimization tips like merging CSS, Js, Optimized Images, lazyload implementation, fewer requests, render-blocking javascript, etc. Best is work out on images, showing webp images in the website helps.
It is very difficult to get full green on Google Insights without making sure you are optimizing every single aspect of your site from server down to code.
I've personally seen some Magento 2.3 sites in green and will try and find that URL's for you however you should not spend all of your time trying to hit 100% as Google has said it is only a minor impact to your SERPs and ranking.
The main thing to focus on is Page Load speed and Google have recently started looking at Page Full Render Speed (time it takes the site to be fully rendered and visible to an end-user).