@Zoeaa123 A mod won't affect a save unless that save is loaded. And its absence won't affect a save that's used it unless that save is loaded. So yes, you could do exactly as you've described.
I cannot say it wouldn't, but a simple solution to your wish is to make two separate user folders - one for mods and one without. The content inside the user folder does not affect the content in other user folders.
The user folder is called The Sims 4, and is located on your computer through this path: Documents>Electronic Arts>The Sims 4.
By naming them differently, the game cannot read them; so to have several, you just name them each a recognizable name, for you, and keep the one you currently want to play named just: The Sims 4.
This is how my Electronic Arts folder look like, my computer is in swedish, but I'm sure you understand it anyway. :
Here is a detailed description of how to create a new folder:
https://sims4.crinrict.com/eng/2014/09/resetting-the-game-to-factory-settings-without-reinstalling/
Please ask if you need more guidance. 🙂
Thank you so much! 🙂
Community Manager
