Is it obligatory to perform ablution for every prayer upon the call to prayer for one who suffers from constant flatulence, which often occurs at the time of ablution and prayer, and does attendance at congregational prayer become waived to avoid harming other worshippers with the smell?

If what you feel is real, then you have سلس (incontinence), and it is permissible for you to perform ablution for each prayer after its time has begun. What exits from you during prayer will not harm you. This is a facilitation due to hardship, and Ibn Hazm says: "Whoever is afflicted with any of what we have mentioned should perform ablution—and it is essential—for every prayer, whether obligatory or supererogatory. Then, nothing that exits from him, whether during prayer or between his ablution and prayer, will be held against him."

If abstaining from food stops the incontinence, then you should abstain from it, as long as it does not cause harm. And it is permissible for someone whose odor harms the worshippers to be absent from congregational prayer.

However, if it is merely doubt or an illusion, then it is a whisper (waswas), and it does not affect the validity of your ablution and prayer, unless you are certain that something has exited.