@josemilio001 If you have Deployment available and energy available, you should be able to activate Overtake mode. That's usually an issue with key bindings as
@Aeghnor pointed out.
We don't get to freely switch between ERS and engine modes (fuel mix in the games) anymore though. First and foremost to reflect the sport: FIA has banned free changing of ICE modes in F1 mid 2020, you cannot change the parameters of fuel combustion (air and fuel mix plus ignition times, basically) in real life, so the game reflects that.
ERS changes are still allowed obviously, but the system we had in the game is way too simple and that ridiculous constant switching we had back in F1 2020 was not only deeply unrealistic, but also not intended by the devs.
This will most likely be revisited in the future to give the players more freedom to set ERS deployment parameters for each track, but hopefully not back to that silly hot swapping we had in F1 2020. Fuel mix won't come back unless FIA backtracks on the "party mode" ban though.
Reiterating, Overtake mode is totally different. If you still have deployment available and the energy to do so, you should be able to trigger Overtake mode. More often than not that's due to a conflict in key bindings in the controller settings.