the z440/420 systems have two normal sata ports (usually blue or grey) and 5 intel "SCU" ports that require the intel RSTe (enterprise) driver to activate windows 10 has built in drivers for both.
does the new SSD show in the bios while booting? if not determine why
during the win to install on the new ssd, does it show the ssd at the select drive to install screen?
are you connecting the ssd to the SATA or SCU port?
last, the z420 can not boot from a nvme drive, the z440 can boot from nvme as it's bios includes the necessary boot code that the z420 lacks, both systems can boot from a sata ssd