​To prevent Sims from acquiring mastery perks in The Sims 4, you can utilize specific mods that allow you to control skill progression and perk acquisition. Here are some options:​

Mod Options to Control Skill Mastery and Perks

1. Lock Skill Gain Progress by Triplis This mod enables you to lock specific skills for individual Sims, effectively halting any further skill progression. By preventing a Sim from reaching the maximum level in a skill, they won’t unlock the associated mastery perks. Features:
   • Lock or unlock specific skills for each Sim.
   • Forget individual skills or all skills entirely.
   • Compatible with skills from various expansion packs.​Patreon+1triplis.github.io+1triplis.github.io
   Usage:
   • Install the mod.
   • Enable cheats in-game by pressing Ctrl + Shift + C and typing testingcheats true.
   • Shift-click on a Sim and select the skill lock options to manage their skills.​triplis.github.io+1Patreon+1
   You can download the mod and find more information here: Lock Skill Gain Progress – Triplis Sims 4 Mods
2. Talents & Weaknesses Mod by Lumpinou This mod allows you to assign talents and weaknesses to Sims, influencing how quickly they gain certain skills. By assigning a skill as a weakness, you can significantly slow down its progression, making it less likely for a Sim to reach mastery and unlock perks. Features:
   • Assign specific skills as talents or weaknesses.
   • Customize skill gain rates for each Sim.
   • Enhance storytelling by creating unique Sim profiles.​Reddit
   Usage:
   • Install the mod.
   • Access the mod’s settings through in-game menus to assign talents and weaknesses.​Reddit+1EA Forums+1
   For more details and download instructions, visit the mod’s page.

Alternative Method: Using Cheats to Remove Mastery Perks

If a Sim has already acquired a mastery perk, you can remove it using cheat codes.​

Steps:

1. Open the cheat console by pressing Ctrl + Shift + C.
2. Type testingcheats true and press Enter.
3. Use the following command to remove a specific trait:​twistedmexi.comtriplis.github.io+1Patreon+1Game Rant kotlinCopyEdittraits.remove_trait TraitName

Replace TraitName with the specific trait code corresponding to the mastery perk you wish to remove.

For a comprehensive list of trait codes related to mastery perks, refer to this guide: The Sims 4: Mastery Perks Cheats – Game Rant