Suggested

change the tire system

change tires, when I see that hard tires allow after 5 laps to go as fast as soft tires .... I find it abnormal

I agree with this... I was running fresh soft tyres and struggling to compete with medium tyres of a similar age to mine. It wasn’t even like I was running heavy fuel (under 30 litres at stop).

Thats down to each drivers development, if your handling and tyre econ is worse then gards can be faster than softs, many ppl research acceleration like its all that matters, there are other settings that make your car faster, try leaving accel and put points on other stuff see what gappens.