Syncthing on ZFS a good case for Deduplication?

I've have a ext4 on LVM on linux RAID based NAS for a decade + that runs syncthing and syncs dozens of devices in my homelab. Works great. I'm finally building it's replacement based on ZFS RAID (first experience with ZFS), so lots of learning.

I know that:

1. Dedup is a good idea in very few cases (I'm aware of the RAM implications. Let's assume I wait until fast-dedup stabilizes and makes it into my system)
2. That most of my syncthing activity is little modifications to existing files
3. That random async writes are harder/slower on a zraid2. Syncthing would be everpresent but the load on the new NAS would be light otherwise.
4. Syncthing works by making new files then deleting the old one by default, but maybe copy_file_range changes this?

My questions are:

1. seeing how ZFS is COW, and syncthing would just constantly be flooding the array with small random writes to existing files, isn't it more efficient to make a dataset out of my syncthing data and enable dedup there only?
2. How does this syncthing setting interact with the ZFS dedup settings? copy_file_range Would it override the ZFS setting or do they both need to be enabled?

Update: Version info (Probably):

• Ubuntu 22.04 or 24.04
• kernel 6.5+
• syncthing 1.27.5
• OpenZFS 2.3