Mouse freezing on loading screen.

@averkayle  My first guess would be another program running in the background while you play.  For example, an app that includes an overlay (Steam, Discord, etc.) could be interfering with Sims 4 or at least with the cursor.  So try playing with only Origin or the EA App and Sims 4 running, nothing else.  You can also disable the in-game overlay for the launcher.  In Origin, it's under Application Settings > Origin in-game; I don't remember where it is for the EA App, but it should be under Settings too.

When you say you reset Windows, did you delete all your personal files and reinstall Windows, or just do some kind of softer reset?

Thank you very much for responding!

I reset windows by deleting all my personal files and re-installing Windows from the get go.

I have not yet re-installed any programs such as Steam or Discord. I don't have a firewall (afaik). When I'm trying to play the game, I don't have any background apps open. As far as background processes go, as far as I can tell (not that I really know anything about this) all the processes are usual background processes for normal computer running.

I just installed Origin and tried playing the game through Origin rather than the EA app and still the same problem. I looked in Origin in-game setting, and I disabled the 'enable origin in game' if that's what you meant. Unfortunately that did not work.

Having reset windows with all personal files deleted and reinstalled windows & the game, I can't understand what's wrong. I'm no computer person so it's highly possible I've mistaken something, but afaik windows & the game are completely re-installed. :-/

In any case, I really appreciate you taking the time to respond to this question, even if you don't know what the problem is. Thank you. :-)

@averkayle  The issue may be the Nvidia graphics driver.  This would be an unusual presentation, but the errors in the dxdiag suggest the driver may be at fault.  Since you have a Surface Book, it's best to use whatever driver Microsoft provides rather than one downloaded from Nvidia.  You can get the package of all the newest drivers here:

https://www.microsoft.com/en-us/download/details.aspx?id=101315

You'll want the Windows 11 version (22000), of course.  Please start by downloading this package and running it—resetting Windows could mean one or more other drivers are not up to date.  Restart your computer after updating, then try to play.  If you get an error when installing, stop here and let me know.  A message that some driver or another is already installed or you have a newer version is fine to ignore; I mean something along the lines of this shouldn't be run on your computer or the installer quit unexpectedly.

Otherwise, if the game still doesn't work, please do a clean uninstall and reinstall of the Nvidia graphics driver, as described here:

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

However, instead of downloading a fresh driver from Nvidia, you'll run the same Microsoft-provided driver package as above.  This time, it should reinstall whichever graphics driver Microsoft has provided rather than a generic one from Nvidia.  Restart your computer again after installing and before trying to play.

Hello,

I tried all the things you suggested, including wiping the nvidia driver and re-installing from the windows surface pack.

Unfortunately, it hasn't really improved much.

The mouse doesn't actually freeze anymore, I can now move it - however, the game doesn't respond to clicking the mouse. I.e., when we got to the home screen there was a dialogue box about game packs currently downloading - I was supposed to be able to click 'okay' to remove the dialogue box, but clicking the 'okay' button didn't do anything.

The fact that the mouse does move now is better than before, but I still can't play the game.

Thanks for all your efforts, though. :-)

YOU ARE A GENIUS!!! :D :D :D

As you can probably guess, my Sims 4 seems to be working now.

Seriously, THANK YOU VERY MUCH!

You didn't have to help me, but you did.  That is awesome of you. I really appreciate it. 

@averkayle  That's great to hear, and you're very welcome.  You can increase the resolution if you want, especially since you have a higher-resolution screen; just keep it at or below the maximum option the game offers.  (It's listed with the other graphics options.)  I'd stay away from fullscreen mode as well, but you can try borderless ("windowed fullscreen") if you want.  If you run into the same issue, just edit options.ini in the same way, plus make sure windowedfullscreen is set to 0 as well.

Maybe helpfull for other users: 
Issue with an surface laptop 3 i5 8G with intel iris hd card

Sims4 loading freezes, not able to control mouse.
When I plugged in external monitor Sims4 runs 

Solution download Intel Graphics command center and disable Adaptive sync (Unlock FPS and AdaptiveSync plus).
Now Sims4 also runs on laptop display.

I hope you can help me a bit further. I tried this when my Sims game was having issues. I updated the width, height, and the fullscreen like you said and it worked at first! After a couple days, I am having the same issue with the loading screen and my mouse freezing once again :/