Almighty Allah informed us of the different acts of worship which should be observed in the manner Allah desires, which is demonstrated in the Quranic verse which reads: (Say (O Muhammad SAW to mankind): "If you (really) love Allah then follow me (i.e. accept Islamic Monotheism, follow the Qur'an and the Sunnah), Allah will love you and forgive you of your sins. And Allah is Oft-Forgiving, Most Merciful.), Al-Emran, 31. It is a sunnah of the prophet to sacrifice after performing prayer not before prayer. This is related by Al-Bukhari on the authority of Al-Baraa, may Allah be pleased with him, who said: (Allah's Messenger (ﷺ) said: The first (act) with which we started our day (the day of 'Id-ul Adha) was that we offered prayer. We then returned and sacrificed the animals and he who did that in fact adhered to our Sunnah (practice). And he who slaughtered the (animal on that day before the 'Id prayer), for him (the slaughtering of animal was directed to the acquiring of) meat for his family, and there is nothing of the sort of sacrifice in it. Abu Burda b. Niyar who had slaughtered (the animal before the 'Id prayer) said: I have a small lamb, of less than one year, but better than that of more than a year. Thereupon Allah's Messenger (ﷺ) qaid: Sacrifice it, but it will not suffice (as a sacrifice) for anyone after you.) Al-Bara' added: The Prophet (ﷺ) said, "Whoever slaughtered (the sacrifice) after the prayer, he slaughtered it at the right time and followed the tradition of the Muslims)

It then become obvious from the narration that sacrificing after prayer is the sunnah, though it is a short time, no more than one hour, for those hastening to slaughter before prayer and miss the sunnah.

This is to know that islam is based on following not following whims.

Also, it is a sunnah of the prophet (PBUH0 not to eat anything except after performing Adha prayer, unlike to Eid Fitr where the prophet used to eat before performing prayer. Abdullah bin Buraidah narrated from his father: (The Prophet would not leave on the Day of Fitr until he ate, and he would not eat on the day of Adha until he prayed.). Imam Ahmad related, ranked Hasan, that the Messenger of Allah (ﷺ) would not go out on the Day of Fitr until he had eaten, and he would not eat on the Day of Nahr (the day of sacrifice) until he came back.)

Let’s observe this sunnah of the Prophet (PBUH).

http://300035.dotdothktrade.tech/en/artical/3407715/95-sunnah-observing-slaughtering-sacrifice-after-eid-prayer