black screen when opening game

Hey!

It's been a while since I last played The Sims 4, maybe around a year. I quit because of lack of space on my MacBook Air, but I have now cleared up about 50GB and therefore decided to play again. Today I installed Origin again and downloaded The Sims 4 (and the few extension packs I have). I started playing a little, with no problem, but I realized I was missing a lot of stuff and therefore decided to download some CC. I ended up spending a lot of time on this and probably downloaded about 2000 or so. As I was going to start my game the logo showed, but then it just turned into a black screen. It stayed like that for about 30 seconds before the game "closed" and the loading mouse appeared. It would stay like that until I force quit the game. I tried a few more times but it didn't work, so I ended up deleting both the game and Origin from my Mac. I re-installed both and tried playing the game - and it went just fine. I then copied the CC that I had downloaded earlier into the mod file, and the game would just show me a black screen when I tried opening it, again. I tried deleting the mods, but the black screen was still there. I then tried deleting and re-installing the game, but now the black screen would show again, and the loading mouse until I force quit the game. I'm very unsure what to do now and hope that someone can help. 

Btw, I have already tried the "repair" on Origin. I would also like to add that I earlier had problems because the Electronic Arts and Sims 4 were separated (one were in my disk and the other one on my iCloud, but I have now fixed this so that they're both on my disk). I'm not sure if this matters but I have a MacBook Air (13-inch, early 2015) where I have macOS Mojave, version 10.14.4. I also made sure that the game is up to date!

Any help would be appreciated, thank you!