Start a offline franchise with the 49ers (Default roster)
Simulate until the draft and then save your game
Start the draft and write down the first 5 picks.
Exit and reload your save.
Go to trades. Trade for the top 5 picks (with teams you wrote down)
You can trade away next year's picks (2021).
After you have the top 5 picks, save your game.
Start the draft. And draft them 1 by 1.
Make sure they have a blue diamond (Hidden Dev Trait)
If they dont have it. Quit and Load your save. Make sure not to select that player again. (Skip and draft the next best)
Once you draft your first player with a blue diamond, you will get the Stud Finder Achievement for drafting a player with a Hidden Dev Trait.
After you have 5 players with hidden dev traits, simulate the rest of the draft. Check the position of the 5 players you drafted and write them down.
Go to the XP sliders and put them to 300 for the positions you drafted
Simulate until Mid Season. Press B when it's at Week 4. This will leave us at Week 5. Go to your Roster. And go down to each Rookie. Press A on the rookie. You will find yourself at the upgrade screen. Use all the skill points you have for that player to upgrade their stats.
Simulate until mid season again. This time without stopping it. After the SIM, go back to your Roster. Check each rookie. If all goes well, You will get lucky and one of them should reveal a X Factor for their hidden trait. Which would net you the achievement
If none of the 5 have X factor for their hidden trait. Then you have bad luck and need to repeat this method. I actually didn't get it until my 2nd try with this method
Here it is in Video Form📺