What happens if you swap a ssd drive into a MacBook Pro that has OS too new for the hardware. Like putting a ssd with Monterey from a 2015 MBP in a 2014 that can only handle Big Sur. Do you have to put BiG Sur on it somehow first?
First, generally when you do this you will get a circle with a slash through it (prohibitory symbol) telling you the OS is bootable, but incompatible with the hardware.
Second, these Apple blade style SSDs cannot always be swapped between different models (some can & some cannot...there is no easy way to tell). Sometimes macOS may refuse to boot even to external media such as Internet Recovery Mode, or it may boot with some other odd behavior. macOS is too smart for itself sometimes because those SSDs will work just fine in other hardware when used with a non-Apple OS such as Linux. Even if macOS will boot with the incorrect blade style SSD, the Apple Diagnostics may report an SSD failure....again because the diagnostics know it is not the correct SSD for that model computer.
Assuming you can boot into Internet Recovery Mode using Command + Option + R, then you can perform a clean install of macOS by first erasing the whole physical SSD before selecting the "Install macOS" option. Within Disk Utility you may need to click "View" and select "Show All Devices" before the physical SSD appears on the left pane of Disk Utility. Erase the whole physical SSD as GUID partition and APFS (top option)....make sure to give the volume a good name.....from the factory it is named "Macintosh HD".
If you can still boot one of these laptops normally, then I highly recommend you create a bootable macOS USB installer while you still can so you have more options in case you have issues with Internet Recovery Mode working correctly.
Create a bootable installer - Apple Support
First, generally when you do this you will get a circle with a slash through it (prohibitory symbol) telling you the OS is bootable, but incompatible with the hardware.
Second, these Apple blade style SSDs cannot always be swapped between different models (some can & some cannot...there is no easy way to tell). Sometimes macOS may refuse to boot even to external media such as Internet Recovery Mode, or it may boot with some other odd behavior. macOS is too smart for itself sometimes because those SSDs will work just fine in other hardware when used with a non-Apple OS such as Linux. Even if macOS will boot with the incorrect blade style SSD, the Apple Diagnostics may report an SSD failure....again because the diagnostics know it is not the correct SSD for that model computer.
Assuming you can boot into Internet Recovery Mode using Command + Option + R, then you can perform a clean install of macOS by first erasing the whole physical SSD before selecting the "Install macOS" option. Within Disk Utility you may need to click "View" and select "Show All Devices" before the physical SSD appears on the left pane of Disk Utility. Erase the whole physical SSD as GUID partition and APFS (top option)....make sure to give the volume a good name.....from the factory it is named "Macintosh HD".
If you can still boot one of these laptops normally, then I highly recommend you create a bootable macOS USB installer while you still can so you have more options in case you have issues with Internet Recovery Mode working correctly.
Create a bootable installer - Apple Support
if the Mac can only run up to big Sur, it probably not boot at all if you swap out the drive for a drive with Monterey. I'm not about to open any of my Macs just to test that theory. but I did attempt to "option boot" into an SSD which has Catalina installed onto an MBP that tops out at El Capitan. on the screen where you choose which macOS you would like to use, it showed me the Catalina boot drive. so I chose that drive. but once it was booted up again, I was not on Catalina, but rather was still on El Capitan.
Swap ssd with too new OS
