CDNs haven't been cached across domains for years. I.e. using a CDN is no faster than a server serving it itself (usually slower because of DNS lookups, but sometimes slightly faster if the geolocation is closer if the DNS was already looked up).
The performance impact of CDNs are definitely a complicated matter and always have been. They aren't a magic solution to any problems unless you're exceeding the origin's available bandwidth, or are serving up something that should be cacheable but somehow can't live without whatever it is that Elementor does that makes it worth every request taking 75 seconds to complete.
CDNs haven't been cached across domains for years. I.e. using a CDN is no faster than a server serving it itself (usually slower because of DNS lookups, but sometimes slightly faster if the geolocation is closer if the DNS was already looked up).