Installing new PCIe m2 SSD on MacBook Pro 2014
start again:
format the new ssd when still outside the mac (you need an cable to usb). Forget all software that came on the disk: all has to go with the format.
Now use a clone app on the mac, like CarbonCopyCloner, to make a clone of your actual disk with everything on it to the still external disk.
When that is ready, shutdown the mac.
Restart while holding the Alt/Option key: the startup menu is displayed: choose the new external disk: when it starts correctly and all is well:
shutdown again, open the mac, take out the "old" disk and put in the new disk, be very careful with the connectors.
Close the mac correctly, startup normally and are ready to continue where you were.
EDIT: it may be that the ssd connection is soldered: then of course you can not do it what I explained.