My experience with btrfs is very different: I'm using it since 2018 on production machines (workstations, laptops and servers), and never had any problem. I use read-only snapshots every day and RAID 0 and 1 configurations in some places without a hassle.

I even had a (known unreliable and crash-prone) RAID 6 configuration using 4 USB thumb drives that had a long life of continuous mp3 transcoding. Finally, the USB hub died, and then I decomissioned the ugly monster (it was mostly for testing).

Maybe I'm lucky (I'm not).
ZFS [...] on one hand, I saw it as a "betrayal" of the Unix philosophy, something foreign within the base system
While undeniably fantastic, I've also had this problem with ZFS: its architecture and terminology have always sounded too alien for the old UNIX whitebeard in me.