Honestly, I've never really understood the appeal of trying to shoehorn RAID into the FS itself. A more traditional softraid has always felt "good enough" to me (especially in this day and age of affordable SSDs).

ZFS in particular seems to push more toward RAIDZ, whereas I'm a bit averse to striping in general nowadays for data recovery/reliability reasons (RAID1 + JBOD is dead-simple to recover, more flexible with heterogeneous disk sizes, and much easier to reason about IMO).