INP and FID Performance

Google is moving from FID to INP, which has two main differences. First of all it doesn't just measure the first interaction it measures every interaction on the page. If nothing happens then it doesn't really count as an interaction. So assuming you've got a long hydration time there's a good probability that the user will try to interact to the page during the hydration even if it's not the first interaction. In fact the site might be even slower because you've got so much JavaScript that it's taking a long time to download and the user is getting really frustrated by clicking stuff all over your website but you're getting excellent FID metrics.