Here’s a useful reference: [[https://beetstech.com/blog/apple-proprietary-ssd-ultimate-guide-to-specs-and-upgrades|The Ultimate Guide to Apple’s Proprietary SSDs] The SSD’s are interchangeable up to a point!
The wrinkle here is Apple has altered both the systems firmware and the drive format from High Sierra onwards so you can encounter issues moving the drives between the systems if the MacOS is not the same on both.
So to get around this you’ll want to setup a bootable OS installer with the OS you want to use [https://www.macworld.com/article/3092900/macs/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive (or newer)] Using it you can re-install the OS.