Game Completely Unplayable after 9/18/2024 Update

Since this has become a collection thread, with many different problems and even more causes, I'll lock it here.

For anyone who encounters infinite loading on a particular lot or set of lots, please remove any lot traits or challenges, especially Off the Grid.  For OtG in particular, please post in this master bug thread:

https://answers.ea.com/t5/Bug-Reports/OPEN-Off-the-grid-lot-challenge-keeps-lot-from-loading-Error-109/td-p/14051036

For anything else, please test with no mods or custom content.  If the game works, head to the Mods forum for help.

https://answers.ea.com/t5/Mods-CC-Issues/bd-p/the-sims-4-game-issues-mods-en

If the game still doesn't work, test a new save, and a new household in an existing save.  If these work, please create a new thread in the Game Issues forum.

https://answers.ea.com/t5/Game-Issues/bd-p/the-sims-4-game-issues-en

If you can't even play a new save, please create a new thread in the Tech forum corresponding to your platform.

https://answers.ea.com/t5/Technical-Issues/ct-p/the-sims-4-technical-issues-en