Sims 4 exe file missing/being deleted

Could anyone please advise me on what I can do to fix this problem?

I own The Sims 4 and multiple packs through digital copies purchased through Origin/EA app. I no longer have Origin as it was uninstalled after a prompt asked me to install the EA App instead a while back.

Up until New Years Day I had no problems launching or playing the game through the EA App.

For the past couple of days I have had issues trying to launch the game. The Sims 4 is showing as installed on the EA App, I click to launch and get this message:

Unable to Start:

Unable to start due to missing game data. Please download The Sims 4 Legacy Edition from Origin

[5de4b8a3:29f00e76:00000000:00000000]

After this, the EA App says:

Your files need repairing

It seems your game files have been corrupted. Kick off a repair so you can get back to your game.

When I try to repair, the progress always starts at 40% and crashes at 49%. The EA App then goes on to say that there was a problem and it needs to try again. This is a never ending cycle.

I have contacted EA support 3 times, who haven't been able to help me really. They have suggested I redownload the EA App (Which I have done), Clear the EA App Caches (Which I have done) and add The Sims 4, EA Launcher & EA Background Service .exe files to my anti-virus exceptions in case it was my anti-virus software blocking it.

I use Avast Anti-virus software and I was unable to locate the TS4 .exe file in my entire computer to add it to the exceptions. Interestingly the Legacy edition of the .exe file exists and is within my exceptions however I cannot load the game on this .exe file.

When I've searched the entire PC, the exe file (TS4_x64.exe) does not exist. When I click on my desktop shortcut it states that it is unable to find the file anymore.

So I've lost the function of launching the game but the game is installed on my computer - which is the issue but I'm unsure why my computer is deleting the .exe file.

In a last ditch attempt last night, I uninstalled and then re-installed all the of the base game and packs, protecting my saves in the process. I was able to play the Sims 4 last night using my old saves.

I have just attempted to relaunch and I am now having the same issue, and now I face the prospect of having to uninstall and re-install the game every time I want to play.

Has anyone got any suggestions of how I can fix this? I thought about making sure the TS4_x64.exe is in my exceptions before relaunching the game once I have the file again but not sure if it is actually my anti-virus software causing the issue.

Thanks