I missed the reply, but.. I was indeed pinpointing the issue that could happen without the stretch mode enabled, as it was suggested as a workaround.. But yeah.
Hello, this question is answered in the documentation.
https://docs.ceph.com/en/squid/rados/operations/stretch-mode/ :
When stretch mode is enabled, PGs will become active only when they peer across CRUSH datacenter``s (or across whichever CRUSH...