I’ve used btrfs many times and always had hiccups. The latest experiment has been using it on Fedora as /home, which has been good, but I’m essentially using it as ext4 2.0 - not exactly a stress test.
I’ve used ZFS extensively and while it can be less flexible IMO it’s a direct consequence of its superior design.
I’m sympathetic to Jim Salters article [0] on the topic even though I’m still rooting for a modern GPL filesystem. Maybe bcachefs [1] will end up taking the crown…