Is it obligatory for someone afflicted with chronic flatulence to hold their flatulence during ablution and prayer? And does he have to repeat ablution if he is unable to do so? And is it permissible for him to perform ablution once before leaving home to perform all prayers? And is it permissible to disregard new matters in acts of worship to avoid obsessive whispers?

You must ignore whisperings (waswas) and turn away from them, because succumbing to them leads to great evil. What you mentioned about continuous flatulence (sals al-reeh) is merely a whispering. You should perform ablution (wudu) and pray normally, without the burden of trying to hold back the wind. Even if what you mentioned were true, it would be sufficient for you to perform ablution after the prayer time enters and pray as many obligatory and supererogatory prayers as you wish with that ablution until the time exits. There is no harm in acting upon the opinion of the Malikis, which allows for performing ablution once before leaving the house and not invalidating ablution by the exit of the time.

Reading fatwas (religious rulings) for beneficial knowledge is useful for getting rid of whisperings. It is also recommended to consult a trusted doctor, in compliance with the Prophet's (peace be upon him) advice to seek treatment.