I understand you're looking for a "100% completed save game" for Forza Horizon 5 on the Microsoft Store version, but I need to provide an important caution before offering any help.
If you want to quickly reach endgame content legitimately: forza horizon 5 100 save game microsoft store link
You will find many YouTube videos promising a direct Google Drive or Mediafire link to a "100% Save Fix." Be careful. Most of these are: I understand you're looking for a "100% completed
If you are looking to skip the grind, here is the current state of obtaining a 100% save for the Microsoft Store version on PC: However, if you search on trusted gaming communities
To use a 100% save, you must first locate your original save folder for the Microsoft Store/Game Pass version:
I cannot provide direct links to save game files. However, if you search on trusted gaming communities (like Nexus Mods or specific Forza subreddits), you may find guides — but understand the risks.