رَّبُّكُمْ أَعْلَمُ بِمَا فِى نُفُوسِكُمْ إِن تَكُونُوا۟ صَٰلِحِينَ فَإِنَّهُۥ كَانَ لِلْأَوَّٰبِينَ غَفُورًا
"Your Lord knows best what is in your souls. If you are righteous — then truly He is forgiving to those who keep turning back."
I give this as my own reading, and its support is the position of the verse: conduct towards parents is a field that can be checked from outside — words, tone of voice, behaviour. Immediately after, the verse looks inward: bimā fī nufūsikum. The state behind the outward behaviour is thus named.
And a door of excuse is opened: in takūnū ṣāliḥīn — if the person is well-intentioned, shortcomings can be forgiven.
أَوَّاب — root أ-و-ب: to return, to come back. Awwāb is an intensive form: one who returns much, who keeps returning.
The root was treated in several places in Ṣād (innahu awwāb, of David (Dāwūd) and of Job (Ayyūb)) and occurred at 50/32 in Qāf (li-kulli awwābin ḥafīẓ). I do not repeat it here.
The choice of the word here is worth recording: the verse does not say tāʾibīn (those who repent), it says awwābīn. The intensive form states that the returning happens not once but again and again.
I record this as an observation: the relationship with parents is a relationship that lasts a lifetime, and it contains repeated failings. The word chosen makes room for a repeated return.