@PositivelySIMful I don't use mods, so hopefully someone who does will post as well. I have a couple of questions though, hope you can answer them: is it the celebrations or the notification of the holidays that's missing; or both? Is it the fixed holidays, like Winterfest, or the random ones, like Talk Like A Pirate day; or both, as well as your own?
I am wondering how this happens. Do you only have one The Sims 4 folder, in Documents>Electronic Arts; or why do you call them save files?
If you only have one The Sims 4 folder, how do you make sure there are savegames with no mods? Do you disable CC and mods in Game Options>Other, and then follow the recommendation to exit the game completely, not just to Main Menu?
I wonder if you would have the same issues if you created a new The Sims 4 folder, by renaming the one you have to for instance The Sims 4Mods. When starting the game anew the game will create a new user folder. Exit the game, and open your old The Sims 4Mods folder; cut the savegames that you do not play with mods in; paste them into the Saves folder in the new The Sims 4 folder. Repair the game again, and twice for good measure. Load the new The Sims 4 folder and see if the holidays are back in your non-mod savegames.
