Is it obligatory to repeat the ghusl if madhy or drops of urine are discharged during ghusl, knowing that this happens almost constantly, causing great hardship? And are ghusl, fasting, and prayer valid if this waswasa (whispering from Satan) is ignored?

You must disregard the whispers of Satan that make you imagine your purity has been nullified or your prayer invalidated. The emission of urine, madhi (pre-seminal fluid), or vaginal discharge during ghusl (ritual bath) does not invalidate it. Rather, it necessitates washing whatever part of the body it touched and performing ablution (wudu) for prayer. If there is incontinence, one should perform ablution after the prayer time begins and then pray. If the discharge stops, one should wait for the time it stops and then purify themselves. All of this applies only if the discharge is real, not merely an imagination. As for fasting, it is not affected by any of this, as purity is not a condition for its validity.