Downloading a standalone .exe from an unofficial "exclusive" link poses significant risks: Forza.net: The official home of Forza
There is no official "exclusive" EXE download. Microsoft does not release standalone EXE files for Forza Horizon 5 outside of their authorized platforms. Any website claiming to have an "official exclusive EXE" is lying.
Subscribe to Xbox Game Pass for PC ($9.99/month). You can download and play the full game instantly.