I strongly recommend sticking with the custom Apple SSD’s. We did some testing a while ago and we found these adapters are not that good (lots of CRC errors). You also likely are not getting the throughput you are expecting.
Here’s a good source for the correct SSD’s: [https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs] Or stick with either OWC or Transcend who took the time to reverse engineer the drives.