Google defines page experience as -aspects that measure how users experience a web page beyond the pure information value of that page-. So this is not so much about how relevant your content is - that is of course also measured and is a hugely important factor - but more about the things around it. Your content can be great, but if your user has to wait too long before the page loads or is flooded with pop-ups and banners he or she will not be very happy about it. Good to know is that Google continues to see the relevance of your content as the most important factor, even if the page experience is not good. But that is no reason to write off page experience as unimportant. Here's the thing: when Google doubts between different pages because they seem to be equally relevant, page experience will be the deciding factor in who 'wins' and is therefore on top of the results page.