Infinite stamina favors the attacker. Police with infinite stamina will never lose a suspect. Crims with infinite stamina will never get caught. The chase becomes an endless, boring circle. The Golden Rule of FiveM "Don't be that guy."
There are public Lua executors that claim to offer "Undetected Stamina." These scripts look like this: fivem infinite stamina
Using a client-side cheat for infinite stamina is the mark of a player who fears losing. Real veterans know that losing because you ran out of breath is realistic. Real veterans know how to manage their stamina, steal a bicycle, or hotwire a car. Infinite stamina favors the attacker