It could be many factors at play. CloudFlare does help with the speed, with it being a CDN it can spread the load of traffic to the website (and it’s assets) much thinner, making it load faster, especially for returning users.
It could also be on a fast hosting provider, such as DigitalOcean - which you wouldn’t necessarily know from performing a WHOIS.
Google Lighthouse reports a very low score, but it’s also percieved load time for the user. If everything on a mobile above the “fold” loads really quickly, it looks faster than perhaps if you were viewing the entire page on a 3G connection on desktop. So many variables are at play.