وَلَوْ تَرَىٰٓ إِذْ وُقِفُوا۟ عَلَى ٱلنَّارِ فَقَالُوا۟ يَٰلَيْتَنَا نُرَدُّ وَلَا نُكَذِّبَ بِـَٔايَٰتِ رَبِّنَا … وَلَوْ رُدُّوا۟ لَعَادُوا۟ لِمَا نُهُوا۟ عَنْهُ
"When they are made to stand at the Fire they say: 'If only we were sent back, and did not cry lies to the signs of our Lord'… Were they sent back, they would return to the very thing they were forbidden."
The same demand was treated at Fāṭir 35/37, al-Sajda 32/12 and al-Muʾminūn 23/99-100, and a table of three was set up there. Al-Anʿām is the fourth link — and what it adds is the statement of what would happen were the demand met.
I record this as my own reading: the verse does not call the remorse false — it accepts that it is genuine, and still says that it will not change the outcome. Because what has changed is not the person but the situation he is in.
وَقَالُوٓا۟ إِنْ هِىَ إِلَّا حَيَاتُنَا ٱلدُّنْيَا وَمَا نَحْنُ بِمَبْعُوثِينَ (29) — the same sentence was treated at al-Jāthiya 45/24; I rely on that treatment.
وَمَا ٱلْحَيَوٰةُ ٱلدُّنْيَآ إِلَّا لَعِبٌ وَلَهْوٌ (32) — laʿib and lahw: treated at al-ʿAnkabūt 29/64, Muḥammad 47/36 and in al-Ḥadīd. And in al-ʿAnkabūt it was answered with the word al-ḥayawān (real life).