Starbunn13 My mods knowledge is pretty limited, so I'd suggest posting here instead:
https://answers.ea.com/t5/Mods-CC-Issues/bd-p/the-sims-4-game-issues-mods-en
While you're waiting for an answer, it's worth testing your mods, using the 50/50 method, in the specific scenario you've found that works without mods but not with them: saving a new household in your main save. That should give you the answer you're looking for, and then you can ask for help fixing your main household with the name of the specific mod that's a problem.
https://modthesims.info/wiki.php?title=Game_Help:Finding_Problem_Custom_Content#The_50.25_Method