1. Close any form of Origin and restart it as administrator

2. Download and run EAAntiCheat.Installer.exe from here:
https://cdn.eaanticheat.ac.ea.com/EAAntiCheat.Installer.exe

3. Uninstall EA Anticheat for FIFA 23 or press Uninstall all to remove the anticheat

4. Run FIFA23.exe as administrator
You can access this by right clicking FIFA 23 in your steam library and clicking on Properties, then go to local files and click on Browse

5. An EA anticheat window will appear, which is going to ask you to install the anticheat

6. After EA Anticheat is installed, run FIFA23.exe as administrator again.

If done correctly, you should be able to play the game.