No problem! And apologies if the linked video was misleading, I included it to highlight the installation procedure.
I also misspoke with regards to the drive, NVMe is incompatible (apologies, first time encountering 2012 Retina MBP SSD Upgrades, had assumed since the port is similar it would be the same :/ )
To clarify, any mSATA drive (which looks like NVMe, albeit mSATA has an additional notch) will work.
“These two models above come with a M.2 AHCI SATA SSD and use a SATA interface. They are definitely not compatible with M.2 PCIe SSD. The PCIe M.2 format looks very similar to the SATA M.2 format but it won't work.
You can upgrade the storage of those models with any SATA M.2 AHCI SSDs - e.g Crucial MX500 sata M.2 - and M.2 to Apple 6+12 adapters. Transcend and OWC also sell upgrades”
QNINE SSD Adapter Card for 2012 Macbook Air and Pro Retina, HDD Hard Disk Drive Converter to 2.5 SATA Support 2012 Year Model A1465 A1466
https://www.amazon.com/dp/B01M16MF9Z/ref=cm_sw_r_cp_api_i_IglzDbM526AY5
^ Thats the first adapter I found, there might be ones with better reviews out there.
Hope this was helpful.