Oh god… I’m going to insult you now, just a heads up.
You idiot, did you look with your eyes closed?
Will I get banned from GTA:O for playing FiveM?
Nope! FiveM does not interact with the Rockstar Online Services other than to validate your game copy the first time you launch it. This validation emulates the game’s interaction, and can not be detected by Rockstar.
It also doesn’t modify your game files at all, even when downloading server assets, so you don’t have to do anything to move between FiveM or GTA:O.