Sims 4 won't open

MoistestBagel0  I've split your post into its own thread so I can keep details straight more easily.  Thanks for providing the dxdiag, which shows a number of serious crashes of the graphics driver.  So please clean-uninstall the current driver and install the newest one available from AMD.  Here's how:

https://crinrict.com/blog/2019/02/clean-re-install-of-graphics-drivers-with-display-driver-uninstaller-ddu.html

You can get the newest driver here:

https://www.amd.com/en/support/downloads/drivers.html/processors/ryzen/ryzen-5000-series/amd-ryzen-5-5600g.html

Please test Sims 4 with no mods or custom content, at least for now: move the Mods folder to the desktop and delete localthumbcache.package.  You don't need to save your progress.  If the game works, you can start testing your mods and cc, if you have any you'd like to keep using.

Josefins  Your dxdiag lists a number of Windows update errors, so please run a couple of basic checks of your Windows system files:

• Hit Windows key-X
• Choose either “PowerShell (Administrator)” or “Windows Terminal (Administrator),” whichever option is offered
• Inside the window that appears, copy and paste “DISM.exe /Online /Cleanup-image /Restorehealth” without quotes, and enter
• The system will start validating soon. If it throws an error, please list it here
• After it reaches 100%, hit Windows key-X again
• Again, choose “PowerShell (Administrator)” or “Windows Terminal (Administrator)”
• Inside the window, copy and paste “sfc /scannow” without quotes, and enter
• Post the message you receive here

Restart your computer, hit Windows key-i, select Update & Security, and click the box to check for updates.  If any install, restart again afterwards.

For the Sims 4 crashes, please try again to play, let the game crash, and then look for a new error in the Reliability Monitor.  Hit Windows key-R and enter "perfmon /rel" without quotes, and you'll see a chart of errors and updates with a column for each day.  Today is on the right.

Look for an error that happened at exactly the time of your most recent Sims 4 crash.  If you find one, double-click it to see more details, then copy that info and paste it into a reply here.  If you don't see a new error, check back in an hour or so—the Reliability Monitor doesn't always update right away.

Once you've done this, try switching back to DirectX 9 mode, which is a check box in the graphics settings, to the right of post processing.  Let me know whether the game crashes in DX9 mode too, and if so, please post the associated Reliability Monitor error.  Double-check the time stamp so you know the error is from DX9 mode specifically.