If you care about the "Time Saver" leaderboards or Club Challenges, using a foreign save might flag your account. Ubisoft generally does not ban for save editing (it is a single-player game), but they do remove invalid leaderboard scores.
The biggest real danger. Never download an executable file claiming to be a "save generator." Only download .save files or .zip archives containing save files. Scan everything with Windows Defender. assassin 39-s creed origins save game level 15
If the Level 15 save was created using a modded executable or a cracked version of the game, it may contain invalid quest flags that break your entire profile. You might find that the crafting table no longer works, or that certain NPCs refuse to speak. If you care about the "Time Saver" leaderboards