Ultrastar 18 SATA with serial start 3WJ firmware upgrade

hi All,
hoping to find You All Well.
Saturday I took 6 SATA Ultrastar 18 Tbyte hard drives, despite having asked steg, the shop where I ordered them in Switzerland, that it was OBVIOUSLY all of contiguous series, they gave me 2 totally different ones with different assembly dates one even of the 2020, and now on my NAS I have a flag that tells me to be careful that the disks are not identical and that their operation in RAIDZ2 could be compromised or not fully supported in case of breakdowns … I wanted to know if you could inform me where I can download the firmware for these HDs Ultrastar SATA 18 Tbyte to see to make them identical at least with the firmware which I think is what could have given me the problem.
thanks !
Gio