What are the rulings concerning dealing with chronic flatulence that afflicts a person at different times of the day, and how should a Muslim act in cases of urinary retention or inability to perform ablution at home, while wishing to catch congregational prayers and supererogatory prayers?

The criterion for being afflicted with سلس (incontinence) is the absence of a known time sufficient to perform the prayer with proper purification.

If the time when the سلس stops is not regular, then your ruling is that of a person afflicted with سلس.

If this time is regular and occurs at the very end of the prayer time, such that the congregational prayer is missed, then you must pray at this time, because the condition of purification takes precedence over performing the congregational prayer.

It is permissible to eat what leads to سلس, unless the intention behind it is to avoid the obligatory purification.