Is the Dozer pool SSD or NVME? I would leave it as is for APPs.
Do you have performance problems with Tank?
A three wide mirror sVDEV would be the match for a Raid-Z2 pool to give the same drive reduntancy of two drives that can fail. You wouldn’t be able to remove sVDEV without recreating the pools, in your case.
iX Systems pool layout whitepaper
Special VDEV (sVDEV) Planning, Sizing, and Considerations
