Page experience
Page experience aggregates the user experience signals retained by Google: Core Web Vitals, HTTPS, absence of intrusive interstitials, and mobile friendliness. It acts as a tiebreaker between pages of comparable relevance.
In practice
Its weight is that of a referee, not an engine: a mediocre but fast page does not beat an excellent but slow one. At equal quality — the common case on competitive queries — experience makes the difference. It is also a sound investment: every gain benefits conversion before it benefits rankings.