WWE 2K23

After every season of MyGM every GM will always receive ONE slammy award & you need win 10 UNIQUE awards.

Sorry I'm making this guide without much info on all the possible Slammies you can win, I just wanted to confirm that you CAN unlock this achievement from MULTIPLE MyGM save files. I just completed season 9 with my main save file & just unlocked it.
I had completeted 10 seasons prior using different save files and I did see a few repeated Slammies, so yes you can use different save files you just need to make sure every year it is a different Slammy you are winning.

For now here are 8 confirmed Slammy requirements I found online:
The Brawler: Most Triple Threat and Fatal 4-Way matches
The Brown Noser: Completed the most Commissioner Goals
The Ringmaster: Largest average crowd size
The Legacy: Most legends hired in a season
The Flip Flopper: Most role changes in a season
The Exec: Most advertising promos
The Caged Beast: Did the most Steel Cage and Hell in a Cell matches
The Bootstrap Puller: Most free agents signed
The Risk Taker: Most injuries in a season

There are also a couple of others I know I earned throughout playing the mode like having the most Cruisers, Bruisers, Fighters, Specialists or Giants. Unfortunately you can't go back to see the Slammies you have already won (otherwise I'd go back and list them sorry), if you wanna help out please add some more Slammy awards in the comments!

EDIT: Thanks to Marcelo Perondi he confirmed using multiple (up to 4) Human controlled GMs in one season DOES count, so you can get 4 Slammies per season & makes this achievement a lot faster to complete!