Note that CF will also route relative to the sites' plan. Enterprise sites are almost always routed to the closest DC, while if that DC is overloaded then lower tier websites, typically just Free sites, will get routed elsewhere (I suppose this is achieved via different anycast ranges where a specific DC is excluded). Although Discord, Signal, etc are almost certainly Enterprise sites.

I have this old site to test this (the list of sites is a bit old): https://cloudflare-test.judge.sh/