Is my Spaces CDN really working as advertised?

I spend some time this morning setting up my first Space and already moved a bunch of files into my bucket. As location, I choose SFO3. To my understanding, the CDN will automatically check my location and give me the files from the server closest to me, right? I upload to the base bucket and DO CDN takes care of the rest, distributing and such.

Btw, I‘m using my own subdomain. I have the same files in a bucket directly with AWS S3, with the location in Frankfurt, Germany. When using DigitalOcean to retrieve instantsearch.js, the file takes about 2s to load. Using my „old“ S3, the same file takes very few milliseconds. This is probably due to the location of the file, which is much closer to me.

2s for a js file is way too long. I assume the CDN is not working as expected, or am I missing something? It seems I retrieve the files from the SFO location, although I assumed the CDN would pick the Frankfurt location, which is closer to me and supported by the DO CDN, according to the docs.