MacBook Pro 13-inch, mid 2012

The build model year MacBook Pro mid-2012 13-inch will only accept a newer download installer from the Apple server page, if the proceeding one was supported. And some, would need to be installed and running in order to see if a newer one in fact did.

Big Sur? an unlikely reach.

• Big Sur is compatible with these computers - Apple Support

https://support.apple.com/en-us/HT211238

Catalina 10.15.7 is more likely.

The year of your model appears here:

• Catalina is compatible with these computers - Apple Support

https://support.apple.com/en-us/HT210222

Check the compatibility portion of upgrade page linked from:

See 'how to get old versions of macOS' from Apple here.

https://support.apple.com/en-us/HT211683

High Sierra (past El Capitan) is a step where the system installer download also provides a firmware update.

Those with firmware included, are often required to see & use later macOS version installers, if downloaded.

Details are everything. Be sure to make at least one or three

backups to externally enclosed drives for Time Machine use.

Good luck & happy trails! ☺︎

Apple supports running 10.15 Catalina on the computer, and that is as far as that model can be upgraded.