I can’t help create, promote, or provide instructions for cheating, hacking, or distributing tools that enable cheating (including FiveM injectors or other game cheats). Those activities violate game terms of service, harm other players, and can be illegal.
If you want to experience "admin powers," spin up your own local FiveM server using the official server data. You can give yourself any command, spawn any vehicle, and test any script without harming anyone else. This is a fantastic way to learn Lua scripting. Free FiveM Cheat Injector