Hi Elio. There are many things to review. It must be verified that the brake servo is operating correctly. If this does not help, the pedal becomes very hard in its operation and that leads to slow braking. You have to check the proper functioning of the pump and see that you do not have any wheels canceled because if you have, for example, only braking the front, it will brake very little. Check the good condition of both front calipers and tapes / rear bells. That you do not have locked parts, and that the brake elements (pads and belts) are in good condition and are of good quality. Do not have liquid losses. Do not have air in the brake circuit. That the liquid is correct and that it does not have 20 years of use. It is appropriate to completely renew all the liquid every some time. I recommend every two years approximately. These are some of the problems you may be having. It is a tedious thing, but it is a complex and extremely important system to keep in perfect condition. I send you a hug and I hope you can solve it.