@Bluebellflora Sorry it's been a hot minute. I've attempted to troubleshoot on my own to try to see the cause of the situation.
I deleted my "The Sims 4" folder again just to see if things would work with a regenerated folder. I did try your advice and just randomly generated a sim and that worked... for a moment. I busied myself with other things and the game finally loaded. I randomly created a sim and was able to successfully move them into a house. Then, I went into "Manage Neighborhood (or whatever, I forget... but simply to change the active family to a different one). After saving two Sim days in one save, I attempted to go back to the main menu since I wanted to start a different save. This is when things got funky.
The loading screen took forever again. I also discovered when I went to Mission Control on my Mac, there were a bunch of "The Sims 4" desktops opened. I'm not sure if this is a normal thing, but this is something I have never noticed before. Because of the loading screen taking forever, I decided to troubleshoot again by removing the "The Sims 4" folder and slowly adding things back in starting with my saves. It appears my saves are the issue... every single save. I tried removing the saves and then replacing the backup versions by deleting "ver0" extension, as recommended by Crinrict's Sims 4 Help Blog. I did this for every single back-up. I also tried everything from the second paragraph again, and it appears that every single save I create is corrupt, which must mean the saving process is faulty... right? It's like no matter what I do, every save isn't able to open and it just makes my gameplay lag indefinitely. You were right in that this is a gameplay issue.
Does this mean I'm forever doomed to just single-play games without ever having any saves? This hasn't been an issue before until a few months ago after I updated my system, added more packs, and updated my game. Is this because of Mac OS updates, or faulty TS4 updates? I feel really at a loss here. I've tried looking at solutions for file save corruptions, but it seems like the most common cause of this is CC or mods, but I play a completely vanilla game on purpose because I don't want any corruptions...