Please install 10.12 Sierra Updates (Folders of Content) mac will restart…
then go to the Apple Logo / About this Mac / System Report… then go to BOOT Rom Version, it should say something like: 483.0.0.0.0
If it’s NOT the case please send us a message.
if the number looks like: 483.0.0.0.0 (or similar) then Proceed to Install High Sierra
then High Sierra Updates ONE BY ONE
then do step 2 again.
If all good. Install Catalina 10.15
Then you can Install Monterey.
drop us a message if you have any questions:
save this instructions please for when you receive the SSD