Sounds like it may be better to break down and get a couple used d3700 sas3 shelf - seems cost of sas3 backplane for those 2u may negate the cost.
Someone suggested the Intel ssd tool and slowly I upgraded firmware and formatted - cleared a few of the errors I was getting..
If you don't mind me asking - what do you think of these ssd on a d3700 shelf and what hba (s) would you suggest? My dl380 has 3x 3.0 and 1x 2.0 pcie - currently slotted with 9211-8i for chassis spinners.. 560+ 10gbe nic, optane 900p (slog may not need now) and the 9201-16e feeding the 1 or 2 shelves..
SAS3 Backplanes for SC216 usually 100-250 on ebay, not that bad overall for a 48x drive setup
SAS2 Backplane for SC216 should be within same price range, and very likely performs the same from what we've discussed here on the forum, even using SAS2 cables, etc, plugged into the newer SAS3 HBA is beneficial.
Yes, intel ssd tool to update firmware, then do a full format (not quick).
LSI 3008 HBA - Can get branded like SuperMicro or the actual LSI labeled, then update\flash.
Performance is going to depend on your usage pattern, sync writes, ZoL or ? how you setup the pools, how you configure\tweak ZFS, etc, etc, etc
Assuming you are going to get 1M IOPs with hardware alone is a big mistake, that's like saying __hardware__ can do x Transactions\second for a database without actually configuring the database for your use case