It depends a LOT on setup and workload unfortunately.
dir on top of ext4 or xfs tends to often be the fastest as there’s none of the copy-on-write overhead that comes with ZFS or btrfs, but then you also don’t get fast snapshots as a consequence of that.
ZFS and btrfs can both be reasonably fast with tweaking but the amount of tweaking is workload dependent. Running a large database on either will often suffer because of copy-on-write so specific files or volumes may need additional config options to improve performance (sometimes at the cost of some of the added reliability).
Then you also have the whole question about what’s backing those pools. ZFS and btrfs will both perform better on dedicated disks or partitions (with ZFS particularly liking disks).