Accidentaly came across some best scored websites, and I wonder ... how this is helpful?
There is a script "Checking your browser" that loads fast and actually Google page speed asses this script but not the real page. It waits for 3 seconds "checking" and then redirects you to the real site.
Example - https://developers.google.com/speed/pagespeed/insights/?hl=bg&url=http%3A%2F%2Fwww.easy-share.com%2F
This is actually designed to prevent bots from overloading a site https://antibot.cloud/ and has nothing to do with page speed insights (I doubt it is effective at any of it's claims but that is a different discussion).
In reality - this "anti bot" service is actually an "anti conversions" facility that will make about 50% of users leave before your site even loads as people have a very short attention span (the rule of thumb is for every second your site takes to load you lose about 10% of your visitors - so that 3 second message has lost you at least 30% of your visitors before your site even starts to load).
If you are asking if having a super fast loading page that displays before the main site (designed to trick Google) is a good idea, no, it is not and it wouldn't work anyway.
The metrics that are actually used to determine your Google rankings are Real User Metrics (RUM) collated into something called the Chrome User Experience Report (CrUX).
So no matter what you do to try and trick Page Speed Insights (a synthetic test) Google will see straight through it and the odds are whatever you do to try and trick Google will end up with a worse user experience and lower conversions.