Why your competitor is having better pagespeed than you
No shop is the same, even if they're running on the same platform. That's because no user let alone audience is the same. That's why it is difficult to compare pagespeed between two shops.
Pagespeed findings
Is RUM data the same as field data?
There is confusion among some people about the distinction between RUM data (Real User Monitoring) and field data. Google refers to field data, while we refer to it as RUM data.
Comparing e-commerce platforms with Google’s real UX data
We can use Google public data to somehow get an idea of the performance of platforms. For free. But there are challenges though when trying to do this. For example when a platform isn't just a website or webshop builder, but maybe both.