How do I upgrade my internal SSD using a third party if my current one is not recognized (failed)? I have a Late 2013 MBP whose 1TB SSD (PCIe) decided to suddenly fail last week. I managed to wipe and reformat the drive via target disk mode, but I cannot reinstall macOS from target disk mode (I didn't know that part beforehand). Even after reseating it multiple times my CPU doesn't even know it's there. 

My plan was to buy a crucial PCIe SSD + Sintech Adapter (Apple uses a propriety PCIe connection) to replace the SSD. In addition to propriety hardware, Apple uses proprietary firmware. The workaround is to update the firmware on the internal SSD before swapping it out, but I cannot access my internal drive from my CPU! 

As a sidenote, I am confident it's not the logic board since I can boot from an external HDD + there are no issues according to the Apple Diagnostics Test. 

How do I upgrade without paying $$$$ to Apple in my current predicament?
Even though it's a "vintage" Mac, it's worth taking it to an Apple Store, if there's one near you, and see if they will look at it and what they would charge. I've often been pleasantly surprised.

Alternatively, you can often find secondhand Apple SSDs for these Macs on sites like eBay.

FWIW, you should be able to install MacOS via target mode from another Mac: I've done so with a 2014 MBP, for instance. The fact that you can't might be a result of the hardware fault.